Cannabis probably evolved in the Himalayan foothills, but its origins are clouded by the plant's early symbiotic relationship with humans. It has been grown for three products - the seeds, which are used as a grainlike food and animal feed and for oil; its fiber, which is used for cloth and rope; and its resin, which is used medically and recreationally since it contains the group of psychoactive substances collectively known as Tetra-hydrocannibinol, usually referred to as THC. Plants grown for seed or fiber are usually referred to as hemp and contain small amounts of THC. Plants grown for THC and for the resin are referred to as marijuana. Use of cannabis and its products spread quickly throughout the world. Marijuana is now cultivated in climates ranging from the Arctic to the equator. Cannabis has been evolving for hundreds of thousands of generations on its own and through informal breeding programs by farmers. A diverse group of varieties has evolved or been developed as a result of breeders' attempts to create a plant that is efficient at producing the desired product, which flourishes under particular environmental conditions. Cannabis easily escapes from cultivation and goes "wild." For instance, in the American midwest, stands of hemp "weed" remain from the 1940's plantings. These plants adapt on a population level to the particular environmental conditions that the plants face; the stand's genetic pool, and thus the plants' characteristics, evolve over a number of generations. Varieties differ in growth characteristics such as height, width, branching traits, leaf size, leaf shape, flowering time, yield, potency, taste, type of hig, and aroma. For the most part, potency is a factor of genetics. Some plants have the genetic potential of producing high grade marijuana and others do not. The goal of the cultivator is to allow the high THC plants to reach their full potential. Marijuana is a fast growing annual plant, although some varieties in some warm areas overwinter. It does best in a well-drained medium, high in fertility. It requires long periods of unobstructed bright light daily. Marijuana is usually dioecious; plants are either male or female, although some varieties are monoecious - they have male and female flowers on the same plant. Marijuana's annual cycle begins with germination in the early spring. The plant grows vigorously for several months. The plant begins to flower in the late summer or early fall and sets seed by late fall. The seeds drop as the plant dies as a result of changes in the weather. Indoors, the grower has complete control of the environment. The cultivator determines when the plants are to be started, when they will flower, whether they are to produce seed and even if they are to bear a second harvest. Marijuana Grower's Handbook - Part 2 of 33 by pH Imbalance "Choosing A Variety" Gardeners can grow a garden with only one or two varieties or a potpourri. Each has its advantages. Commercial growers usually prefer homogenous gardens because the plants tatse the same and mature at the same time. These growers usually choose fast maturing plants so that there is a quick turnaround. Commercial growers often use clones or cuttings from one plant so that the garden is genetically idential; the clones have exactly the same growth habits and potency. Homegrowers are usually more concerned with quality than with fast maturity. Most often, they grow mixed groups of plants so they have a selection of potency, quality of the high, and taste. Heterogeneous gardens take longer to mature and have a lower yield than homogenous gardens. They take more care, too, because the plants grow at different rates, have different shapes and require varying amounts of space. The plants require individual care. Marijuana grown in the United States is usually one of two main types: inidica or sativa. Indica plants originated in the Hindu-Kush valleys in central Asia, which is located between the 25-35 latitudes. The weather there is changeable. One year there may be drought, the next it might be cloudy, wet, rainy or sunny. For the population to survive, the plant group needs to have individuals which survive and thrive under different conditions. Thus, in any season, no matter what the weather, some plants will do well and some will do poorly. Indica was probably developed by hash users for resin content, not for flower smoking. The resin was removed from the plant. An indication of indica's development is the seeds, which remain enclosed and stick to the resin. Since they are very hrd to disconnect from the plant, they require human help. Wild plants readily drop seeds once they mature. Plants from the same line from equatorial areas are usually fairly uniform. These include Colombians and central Africans. Plants from higher latitudes of the same line sometimes have very different characteristics. These include Southern Africans, Northern Mexicans, and indicas. The plants look different from each other and have different maturities and potency. The ratio of THC (the ingredient which is psychoactive) to CBD (its precursor, which often leaves the smoker feeling disoriented, sleepy, drugged or confused) also varies. High latitude sativas have the same general characteristics: they tend to mature early, have compact short branches and wide, short leaves which are dark green, sometimes tinged purple. Indica buds are usually tight, heavy, wide and thick rather than long. They smell "stinky", "skunky", or "pungent" and their smoke is thick - a small toke can induce coughing. The best indicas have a relaxing "social high" which allow one to sense and feel the environment but do not lead to thinking about or analyzing the experience. Cannabis sativa plants are found throughout the world. Potent varieties such as Colombian, Panamanian, Mexican, Nigerian, Congolese, Indian and Thai are found in equatorial zones. These plants require a long time to mature and ordinarily grow in areas where they have a long season. They are usually very potent, containing large quanities of THC and virtually no CBD. They have long, medium-thick buds when they are grown in full equatorial sun, but under artificial light or even under the temperate sun, the buds tend to run (not fill out completely). The buds usually smell sweet or tangy and the smoke is smooth, sometimes deceptively so. The THC to CBD ratio of sativa plants gets lower as the plants are found further from the equator. Jamaican and Central Mexican varieties are found at the 15-20th latitudes. At the 30th latitude, varieties such as Southern African and Northern Mexican are variable and may contain equal amounts of THC and CBD, giving the smoker and buzzy, confusing high. These plants are used mostly for hybridizing. Plants found above the 30th latitude usually have low levels of THC, with high levels of CBD and are considered hemp. If indica and sativa varieties are considered opposite ends of a spectrum, most plants fall in between the spectrum. Because of marijuana and hemp's long symbiotic relationship with humans, seeds are constantly procured or traded so that virtually all populations have been mixed with foreign plants at one time or another. Even in traditional marijuana-growing countries, the marijuana is often the result of several cross lines. Jamaican ganja, for example, is probably the result of crosses between hemp, which the English cultivated for rope, and Indian ganja, which arrived with the Indian immigrants who came to the country. The term for marijuana in Jamaic in ganja, the same as in India. The traditional Jamaican term for the best weed is Kali, named for the Indian killer goddess. Marijuana Grower's Handbook - Part 3 of 33 "Growth and Flowering" The cannabis plant regulates its growth and flowering stages by measuring the changes in the number of hours of uniterrupted darkness to determine when to flower. The plant produces a hormone (phytochrome) begining at germination. When this chemical builds up to a critical level, the plant changes its mode from vegetative growth to flowering. This chemical is destroyed in the presence of even a few moments of light. During the late spring and early summer there are many more hours of light than darkness and the hormone does not build up to a critical level. However, as the days grow shorter and there are longer periods of uniterrupted darkness, the hormone builds up to a critical level. Flowering occurs at different times with different varieties as a result of the adaptation of the varieties to the environment. Varieties from the 30th latitude grow in an area with a temperate climate and fairly early fall. These plants usually trigger in July or August and are ready to harvest in September or October. Southern African varieties often flower with as little as 8 or 9 hours of darkness/15 to 16 hours of light. Other 30th latitude varieties including most indicas flower when the darkness cycle lasts a minimum of 9 to 10 hours. Jamaican and some Southeast Asian varieties will trigger at 11 hours of darkness and ripen during September or October. Equatorial varieties trigger at 12 hours or more of darkness. This means that they will not start flowering before late September or early October and will not mature until late November or early December. Of course, indoors the plants' growth stage can be regulated with the flick of a switch. Nevertheless, the plants respond to the artificial light cycle in the same way that they do to the natural seasonal cycles. The potency of the plant is related to its maturity rather than chronological age. Genetically identical 3 month and 6 month-old plants which have mature flowers have the same potency. Starting from seed, a six month old plant flowers slightly faster and fills out more than a 3 month old plant. Marijuana Grower's Handbook - Part 4 of 33 "Choosing a Space" Almost any area can be converted to a growing space. Attics, basements, spare rooms, alcoves and even shelves can be used. Metal shacks, garages and greenhouses are ideal areas. All spaces must be located in an area inaccessible to visitors and invisible from the street. The ideal area is at least 6 feet high, with a minimum of 50 square feet, an area about 7 feet by 7 feet. A single 1,000 watt metal halide or sodium vapor lamp, the most efficient means of illuminating a garden, covers an area this size. Gardeners who have smaller spaces, at least one foot wide and several feet long, can use fluorescent tubes, 400 watt metal halides, or sodium vapor lamps. Gardeners who do not have a space even this large to spare can use smaller areas (See part 17 - "Novel Gardens"). Usually, large gardens are more efficient than small ones. The space does not require windows or outside ventilation, but it is easier to set up a space if it has one or the other. Larger growing areas need adequate ventilation so that heat, oxygen, and moisture levels can be controlled. Greenhouses usually have vents and fans built in. Provisions for ventilation must be made for lamp-lit enclosed areas. Heat and moisture buildup can be extraordinary. During the winter in most areas, the heat is easily dissipated; however, the heat buildup is harder to deal with in hot weather. Adequate ventilation or air coolers are the answer. Marijuana Grower's Handbook - Part 5 of 33 "Preparing the Space" The space is the future home and environment of the plants. It should be cleaned of any residue or debris which might house insects, parasites or diseases. If it has been contaminated with plant pests it can be sprayed or wiped down with a 5% bleach solution which kills most organisms. The room must be well-venitalted when this operation is going on. The room will be subject to high humidity so any materials such as clothing which might be damaged by moisture are removed. Since the plants will be watered, and water may be spilled, the floors and any other areas that may be water damaged should be covered with linoleum or plastic. High grade 6 or 8 mil polyethylene drop cloths or vinyl tarps protect a floor well. The plastic should be sealed with tape so that no water seeps to the floor. The amount of light delivered to the plant rises dramatically when the space is enclosed by reflective material. Some good reflective materials are flat white paint, aluminum foil (the dull side so that the light is diffused), white cardboard, plywood painted white, white polyethylene, silvered mylar, gift wrap, white cloth, or silvered plastic such as Astrolon. Mterials can be taped or tacked onto the walls, or hung as curtains. All areas of the space should be covered with reflective material. The walls, ceiling and floors are all capable of reflecting light and should be covered with reflective material such as aluminum foil. It is easiest to run the material vertically rather than horizontally. Experienced growers find it convenient to use the wide, heavy-duty aluminum foil or insulating foil (sold in wide rolls) in areas which will not be disturbed and plastic or cloth curtains where the material will be moved. Windows can be covered with opaque material if a bright light emanating from the window would draw suspicion. If the window does not draw suspicion and allows bright light into the room, it should be covered with a translucent material such as rice paper, lace curtains, or aquarium crystal paint. Garages, metal buildings, or attics can be converted to lighthouses by replacing the roof with fiberglass greenhouse material such as Filon. These translucent panels permit almost all the light to pass through but diffuse it so that there is no visible image passing out while there is an even distribution of light coming in. A space with a translucent roof needs no artificial lighting in the summer and only supplemental lighting during the other seasons. Overhead light entering from askylight or large window is very helpful. Light is utilized best if it is diffused. Concrete and other cold floors should be covered with insulating material such as foam carpet lining, styrofoam sheeting, wood planks or wooden palettes so that the plant containers and the roots are kept from getting cold. Marijuana Grower's Handbook - Part 6 of 33 "Plant Size and Spacing" Marijuana varieties differ not only in their growth rate, but also in their potential size. The grower also plays a role in determining the size of the plants because the plants can be induced to flower at any age or size just by regulating the number of hours of uninterrupted darkness that the plants receive. Growers have different ideas about how much space each plant needs. The closer the plants are spaced, the less room the individual plant has to grow. Some growers use only a few plants in a space, and they grow the plants in large containers. Other growers prefer to fill the space with smaller plants. Either method works, but a garden with smaller plants which fills the space mroe completely probably yields more in less time. The total vegetative growth in a room containing many small sized plants is greater than a room containing only a few plants. Since each plant is smaller, it needs less time to grow to its desired size. Remember that the gardener is interested in a crop of beautiful buds, not beautiful plants. The amount of space a plant requires depends on the height the plants are to grow. A plant growing 10 feet high is going to be wider than a 4 foot plant. The width of the plant also depends on cultivation practices. Plants which are pruned grow wider than unpruned plants. The different growth characteristics of the plants also affect the space required by each plant. In 1- or 2-light gardens, where the plants are to grow no higher than 6 feet, plants are given between 1 and 9 square feet of space. In a high greenhouse lit by natural light, where the plants grow 10-12 feet high, the plants may be given as much as 80 to 100 square feet. Marijuana Grower's Handbook - part 7 of 33 "Planting Mixes" One of the first books written on indoor growing suggested that the entire floor of a grow room be filled with soil. This method is effective but unfeasible for most cultivators. Still, the growers have a wide choice of growing mediums and techniques; they may choose between growing in soil or using a hydroponic method. Most growers prefer to cultivate their plants in containers filled with soil, commercial mixes, or their own recipe of soil, fertilizers, and soil conditioners. These mixes vary quite a bit in their content, nutrient values, texture, pH, and water-holding capacity. Potting soil is composed of topsoil, which is a natural outdoor composite high in nutrients. It is the top layer of soil, containing large amounts of organic material such as humus and compost as well as minerals and clays. Topsoil is usually lightened up so that it does not pack. This is done by using sand, vermiculite, perlite, peat moss and/or gravel. Potting soil tends to be very heavy, smell earthy and have a rich dark color. It can supply most of the nutrients that a plant needs for the first couple of months. Commercial potting mixes are composites manufactured from ingredients such as bark or wood fiber, composts, or soil conditioners such as vermiculite, perlite, and peat moss. They are designed to support growth of houseplants by holding adequate amounts of water and nutrients and releasing them slowly. Potting mixes tend to be low in nutrients and often require fertilization from the outset. Many of them may be considered hydroponic mixes because the nutrients are supplied by the gardener in a water solution on a regular basis. Texture of the potting mix is the most important consideration for containerized plants. The mixture should drain well and allow air to enter empty spaces so that the roots can breathe oxygen. Mixes which are too fine may become soggy or stick together, preventing the roots from obtaining the required oxygen. A soggy condition also promotes the growth of anaerobic bacteria which release acids that eventually harm the roots. A moist potting mix with good texture should form a clump if it is squeezed in a fist; then with a slight poke the clod should break up. If the clod stays together, soil conditioners are required to loosen it up. Vermiculite, perlite or pea-sized styrofoam chips will serve the purpose. Some growers prefer to make their own mixes. These can be made from soil, soil conditioners, and fertilizers. Plants grown in soil do not grow as quickly as those in hydroponic mixes. However, many growers prefer soil for aesthetic reasons. Good potting mixes can be made from topsoil fairly easy. Usually it is easier to buy topsoil than to use unpasteurized topsoil which contains weed seeds, insects and disease organisms. Outdoors, these organisms are kept in check, for the most part, by the forces of nature. Bringing them indoors, however, is like bringing them into an incubator, where many of their natural enemies are not around to take care of them. Soil can be sterilized using a 5% bleach solution poured through the medium or by being steamed for 20 minutes. Probably the easiest way to sterilize soil is to use a microwave. It is heated until it is steaming, about 5 minutes for a gallon or more. Potting soils and potting mixes vary tremendously in composition, pH and fertility. Most mixes contain only small amounts of soil. If a package is marked "potting soil", it is usually made mostly from topsoil. If the soil clumps up it should be loosened using sand, perlite or styrofoam. One part amendment is used to 2-3 parts soil. Additives listen in Chart 7-2 may also be added. Here is a partial list of soil conditioners: Foam Foam rubber can be used in place of styrofoam. Although it holds water trapped between its open cells it also holds air. About 1.5 parts of foam rubber for every part of styrofoam is used. Pea-size pieces or smaller should be used. Gravel Gravel is often used as a sole medium in hydroponic systems because it is easy to clean, never wears out, does not "lock up" nutrients, and is inexpensive. It is also a good mix ingredient because it creates large spaces for airpockets and gives the mix weight. Some gravel contains limestone (see "Sand"). This material should not be used. Lava Lava is a preferred medium on its own or as a part of a mix. It is porous and holds water both on its surface and in the irregular spaces along its irregular shape. Lava is an ideal medium by itself but is sometimes considered a little too dry. To give it moremoisture-holding ability, about one part of wet vermiculite ismixed with 3 to 6 parts lava. The vermiculite will break up and coat the lava, creating a mdeium with excellent water-holding abilities and plenty of air spaces. If the mix is watered from the top, the vermiculite will wash down eventually, but if it is watered from the bottom it will remain. Perlite Perlite is an expanded (puffed) volcanic glass. It is lightweight with many peaks and valleys on its surface, where it traps particles of water. However, it does not absorb water into its structure. It does not break down easily and is hard to the touch. Perlite comes in several grades with the coarser grade being better for larger containers. perlite is very dusty when dry. To eliminate dust, the material is watered to saturation with a watering can or hose before it is removed from the bag. Use of masks and respirators is important. Rockwool Rockwool is made from stone which has been heated then extruded into think strands which are something like glass wool. It absorbs water like a wick. It usually comes in blocks or rolls. It can be used in all systems but is usually used in conjunction with drop emitters. Growers report phenomenal growth rates using rockwool. It is also very convenient to use. The blocks are placed in position or it is rolled out. Then seeds or transplants are placed on the material. Sand Sand is a heavy material which is often added to a mixture to increase its weight so that the plant is held more firmly. It promotes drainage and keeps the mix from caking. Sand comes in several grades too, but all of them seem to work well. The best sand to use is composed of quartz. Sand is often composed of limestone; the limestone/sand raised pH, causing micronutrients to precipitate, making them unavailable to the plants. It is best not to use it. Limestone-containing sand can be "cured" by soaking in a solution of water and superphosphate fertilizer which binds with the surface of the lime molecule in the sand, making the molecule temporarily inert. One pound of superphosphate is used to 5 gallons of water. It dissolves best in hot water. The sand should sit in this for 6-12 hours and then be rinsed. Superphosphate can be purchased at most nurseries. Horticultural sand is composed of inert materials and needs no curing. Sand must be made free of salt if it came from a salt-water area. Sphagnum Moss Sphagnum or peat moss is gathered from bogs in the midwest. It absorbs many times its own weight in water and acts as a buffer for nutrients. Buffers absorb the nutrients and hold large amounts in their chemical structure. The moss releases them gradually as they are used by the plant. If too much nutrient is supplied, the moss will act on it and hold it, preventing toxic buildups in the water solution. Moss tends to be acidic so no more than 20% of the planting mix should be composed of it. Styrofoam Pellets Styrofoam is a hydrophobic material (it repels water) and is an excellent soil mix ingredient. It allows air spaces to form in the mix and keeps the materials from clumping, since it does not bond with other materials or with itself. One problem is that it is lighter than water and tends to migrate to the top of the mix. Styrofoam is easily used to adjust the water-holding capacity of a mix. Mixes which are soggy or which hold too much water can be "dried" with the addition of styrofoam. Styrofoam balls or chips no larger than a pea should be used in fine-textured mixtures. Larger styrofoam pieces can be used in coarse mixes. Vermiculite Vermiculite is porcessed puffed mica. It is very lightweight but holds large quantities of water in its structure. Vermiculite is available in several size pieces. The large size seems to permit more aeration. Vermiculite breaks down into smaller particles over a period of time. Vermiculite is sold in several grades based on the size of the particles. The fine grades are best suited to small containers. In large containers, fine particles tend to pack too tightly, not leaving enough space for air. Coarser grades should be used in larger containers. Vermiculite is dusty when dry, so it should be wet down before it is used. Mediums used in smaller containers should be able to absorb more water than mediums in larger containers. For instance, seedlings started in 1 to 2 inch containers can be planted in plain vermiculite or soil. Containers up to about one gallon can be filled with a vermiculite-perlite or soil-perlite mix. Containers larger than that need a mix modified so that it does not hold as much water and does not become soggy. The addition of sand, gravel, or styrofoam accomplishes this very easily. Here are lists of different mediums suitable for planting: Below is a list of the moist mixtures, suitable for the wick system, the reservoir system and drop emitters which are covered in part 9. Chart 7-1-A: Moist Planting Mixes 4 parts topsoil, 1 part vermiculite, 1 part perlite. Moist, contains medium-high amounts of nutrients. Best for wick and hand-watering. 3 parts topsoil, 1 part peat moss, 1 part vermiculite, 1 part perlite, 1 part styrofoam. Moist but airy. Medium nutrients. Best for wick and hand-watering. 3 parts vermiculite, 3 parts perlite, 1 part sand, 2 parts pea-sized gravel. Moist and airy but has some weight. Good for all systems, drains well. 5 parts vermiculite, 5 parts perlite. Standard mix, moist. Excellent for wick and drop emitters systems though it works well for all systems. 3 parts vermiculite, 1 part perlite, 1 part styrofoam. Medium dry mix, excellent for all systems. 2 parts vermiculite, 1 part perlite, 1 part styrofoam, 1 part peat moss. Moist mix. 2 parts vermiculite, 2 parts perlite, 3 parts styrofoam, 1 part sphagnum moss, 1 part compost. Medium moisture, small amounts of slow releasing nutrients, good for all systems. 2 parts topsoil, 2 parts compost, 1 part sand, 1 part perlite. Medium-moist, high in slow-release of organic nutrients, good for wick and drip systems, as well as hand watering. 2 parts compost, 1 part perlite, 1 part sand, 1 part lava. Drier mix, high in slow-release of nutrients, drains well, good for all systems. 1 part topsoil, 1 part compost, 2 parts sand, 1 part lava. Dry mix, high in nutrients, good for all systems. 3 parts compost, 3 parts sand, 2 parts perlite, 1 part peat moss, 2 parts vermiculite. Moist, mid-range nutrients, good for wick systems. 2 parts compost, 2 parts sand, 1 part styrofoam. Drier, high nutrients, good for all systems. 5 parts lava, 1 part vermiculite. Drier, airy, good for all systems. Here are some drier mediums suitable for flood systems as well as drip emitters (hydroponic systems covered in part 9). Chart 7-1-B: Flood System/Drip Emitter Mixes Lava Pea sized gravel Sand Mixes of any or all of the above. Manure and other slow-releasing natural fertilizers are often added to the planting mix. With these additives, the grower needs to use ferilizers only supplementally. Some of the organic amendments are listed in the following chart. Organic amendments can be mixed but should not be used in amounts larger than those recommended because too much nutrient can cause toxicity. Some growers add time-release fertilizers to the mix. These are formulated to release nutrients over a specified period of time, usually 3, 4, 6 or 8 months. The actual rate of release is regulated in part by temperature, and since house temperatures are usually higher than outdoor soil temperatures, the fertilizers used indoors release over a shorter period of time than is noted on the label. Gardeners find that they must supplement the time-release fertilizer formulas with soluble fertilizers during the growing season. Growers can circumvent this problem by using time-release fertilizer suggested for a longer period of time than the plant cycle. For instance, a 9 month time-release fertilizer can be used in a 6 month garden. Remember that more fertilizer is releasing faster, so that a larger amount of nutrients will be available than was intended. These mixes are used sparingly. About one tablespoon of dolomite limestone should be added for each gallon of planting mix, or a half cup per cubic foot of mix. This supplies the calcium along with mangesium, both of which the plants require. If dolomite is unavailable, then hydrated lime or any agricultural lime can be used. Chart 7-2: Organic Amendments +-----------------+-----+-----+------+-------------------------------------+ | Amendment | N | P | K | 1 Part : X Parts Mix | | Cow Manure | 1.5 | .85 | 1.75 | Excellent condition, breaks down | | | | | | over the growing season. 1:10 | +-----------------+-----+-----+------+-------------------------------------+ | Chicken Manure | 3 | 1.5 | .85 | Fast acting. 1:20 | +-----------------+-----+-----+------+-------------------------------------+ | Blood Meal | 15 | 1.3 | .7 | N quickly available. 1:100 | +-----------------+-----+-----+------+-------------------------------------+ | Dried Blood | 13 | 3 | 0 | Very soluble. 1:100 | +-----------------+-----+-----+------+-------------------------------------+ | Worm Castings | 3 | 1 | .5 | Releases N gradually. 1:15 | +-----------------+-----+-----+------+-------------------------------------+ | Guano | 2-8 | 2-5 | .5-3 | Varies alot, moderately soluble. | | | | | | For guano containing 2% nitrogen, | | | | | | 1:15. For 8% nitrogen, 1:40 | +-----------------+-----+-----+------+-------------------------------------+ | Cottonseed Meal | 6 | 2.5 | 1.5 | Releases N gradually. 1:30. | +-----------------+-----+-----+------+-------------------------------------+ | Greensand | 0 | 1.5 | 5 | High in micronutrients. Nutrients | | | | | | available over the season. 1:30 | +-----------------+-----+-----+------+-------------------------------------+ | Feathers | 15 | ? | ? | Breaks down slowly. 1:75 | +-----------------+-----+-----+------+-------------------------------------+ | Hair | 17 | ? | ? | Breaks down slowly. 1:75 | -------------------------------------------------------------------------------- N = Nitrogen * P = Phosphorous * K = Potassium Marijuana Grower's Handbook - part 8 of 33 "Hydroponics vs. Soil Gardening" Plants growing in the wild outdoors obtain their nutrients from the breakdown of complex organic chemicals into simpler water-soluble forms. The roots catch the chemicals using a combination of electrical charges and chemical manipulation. The ecosystem is generally self-supporting. For instance, in some tropical areas most of the nutrients are actually held by living plants. As soon as the vegetation dies, bacteria and other microlife feast and render the nutrients water-soluble. They are absorbed into the soil and are almost immediately taken up by higher living plants. Farmers remove some of the nutrients from the soil when they harvest their crops. In order to replace those nutrients they add fertilizers and other soil additives. [pH : perhaps shake would be good fertilizer for one's next crop] Gardeners growing plants in containers have a closed ecology system. Once the plants use the nutrients in the medium, their growth and health is curtailed until more nutrients become available to them. It is up to the grower to supply the nutrients required by the plants. The addition of organic matter such as compost or manure to the medium allows the plant to obtain nutrients for a while without the use of water-soluble fertilizers. However, once these nutrients are used up, growers usually add water-soluble nutrients when they water. Without realizing it, they are gardening hydroponically. Hydroponics is the art of growing plants, usually without soil, using water-soluble fertilizers as the main or sole source of nutrients. The plants are grown in a non-nutritive medium such as gravel or sand or in lightweight materials such as perlite, vermiculite or styrofoam. The advantages of a hydroponic system over conventional horticultural methods are numerous: dry dpots, root drowning and soggy conditions do not occur. Nutrient and pH problems are largely eliminated since the grower maintains tight control over their concentration; there is little chance of "lockup" which occurs when the nutrients are fixed in the soil and unavailable to the plant; plants can be grown more conveniently in small containers; and owing to the fact that there is no messing around with soil, the whole operation is easier, cleaner, and much less bothersome than when using conventional growing techniques. Marijuana Grower's Handbook - part 9 of 33 "Hydroponic Systems" Most hydroponic systems fall into one of two broad categories: passive or active. Passive systems such as reservoir or wick setups depend on the molecular action inherent in the wick or medium to make water available to the plant. Active systems which include the flood, recirculating drop and aerated water systems, use a pump to send nourishment to the plants. Most commercially made "hobby" hydroponic systems designed for general use are shallow and wide, so that an intensive garden with a variety of plants can be grown. But most marijuana growers prefer to grow each plant in an individual container. PASSIVE HYDROPONIC SYSTEMS The Wick System The wick system is inexpensive, easy to set up and easy to maintain. The principle behind this type of passive system is that a length of 3/8 to 5/8 inch thick braided nylon rope, used as a wick, will draw water up to the medium and keep it moist. The container, which can be an ordinary nursery pot, holds a rooting medium and has wicks runing along the bottom, drooping through the holes at the bottom, reaching down into a reservoir. Keeping the holes in the container small makes it difficult for roots to pentrate to the reservoir. The amount of water delivered to the medium can be increased by increasing the number, length, or diameter of the wicks in contact with the medium. A 1 gallon container needs only a single wick, a three gallon container should have two wicks, a five gallon container, three wicks. The wick system is self regulating; the amount of water delivered depnds on the amount lost through evaporation or transpiration. Each medium has a maximum saturation level. Beyond that point, an increase in the number of wicks will not increase the moisture level. A 1-1-1 combination of vermiculite, perlite, and styrofoam is a convenient medium because the components are lightweight and readily available. Some commercial units are supplied with coarse vermiculite. To increase weight so that the plant will not tip the container over when it gets large, some of the perlite in the recipe can be replaced with sand. The bottom inch or two of the container should be filled only with vermiculite, which is very absorbent, so that the wicks have a good medium for moisture transfer. Wick systems are easy to construct. The wick should extend 5 inches or more down from the container. Two bricks, blocks of wood, or styrofoam are placed on the bottom of a deep tray (a plastic tray or oil drip pan will do fine.) Then the container is placed on the blocks so that the wicks are touching the bottom of the tray. The tray is filled with a nutrient/water solution. Water is replaced in the tray as it evaporates or is absorbed by the medium through the wick. A variation of this system can be constructed using an additional outer container rather than a tray. With this method less water is lost due to evaporation. To make sure that the containers git together and come apart easily, bricks or wood blocks are placed in the bottom of the outer container. The container is filled with the nutrient/water solution until the water comes to just below the bottom of the inner container. Automating this system is simple to do. Each of the tray or bottom containers is connected by tubing to a bucket containing a float valve such as found in toilets. The valve is adjusted so that it shuts off when the water reaches a height about 1/2 inch below the bottom of the growing containers. The bucket with the float valve is connected to a large reservoir such as a plastic garbage can or 55 gallon drum. Holes can be drilled in the containers to accomodate the tubing required, or the tubes can be inserted from the top of the containers or trays. The tubes should be secured or weighted down so that they do not slip out and cause floods. The automated wick system works as a siphon. To get it started, the valve container is primed and raised above the level of the individual trays. Water flows from the valve to the plant trays as a result of gravity. Once the containers have filled and displaced air from the tubes, the water is automatically siphoned and the valve container can be lowers. Each container receives water as it needs it. A simpler system can be devised by using a plastic kiddie pool and some 4x4's or a woodem pallet. Wood is placed in the pool so that the pots sit firmly on the board; the pool is then filled with water up to the bottom of the pots. The wicks move the water to the pots. Wick systems and automated wick systems are available from several manufacturers. Because they require no moving parts, they are generally reliable although much more expensive than homemande ones, which are very simple to make. Wick system units can be filled with any of the mixes found in Chart 7-1-A. The Reservoir System The reservoir system is even less complex than the wick system. For this setup all a grower needs to do is fill the bottom 2 or 3 inches of a 12 inch deep container with a coarse, porous, inert medium such as lava, ceramic beads or chopped unglazed pottery. The remaining portion is filled with one of the mixes containing styrofoam. The container is placed in a tray, and sits directly in a nutrient-water solution 2-3 inches deep. The system is automated by placing the containers in a trough or large tray. Kiddie pools can also be used. The water is not replaced until the holding tray dies. Passive systems should be watered from the top down once a month so that any buildup of nutrient salts caused by evaporation gets washed back to the bottom. ACTIVE HYDROPONIC SYSTEMS Active systems move the water using mechanical devices in order to deliver it to the plants. There are many variations on active systems but most of them fall into one of three categories: flood systems, drip systems, or nutrient film systems. The Flood System The flood system is the type of unit that most people think of when hydroponics is mentioned. The system usually has a reservoir which periodically empties to flood the container or tub holding the medium. The medium holds enough moisture between irrigations to meet the needs of the plant. Older commercial greenhouses using this method often held long troughs or beds of gravel. Today, flood systems are designed using individual containers. Each container is attached to the reservoir using tubing. A simple flood system can be constructed using a container with a tube attached at the bottom of a plastic container [pH: that which the plant is placed in] and a jug. The tube should reach down to the jug, which should be placed below the bottom of the growing container. To water, the tube is held above the container so that it doesn't drop. The water is poured from the jug into the container. Next, the tube is placed in the jug and put back into position, below the growing container. The water will drain back into the jug. Of course, not as much will drain back in as was poured out. Some of the water was retained in the growing unit. Automating this unit is not difficult. A two-holed stopper is placed in the jug. A tube from the growing unit should reach the bottom of the reservoir container. Another tube should be attached to the other stopper hole and then to a small aquarium-type air pump which is regulated by a timer. When the pump turns on, it pushes air into the jug, forcing the water into the container. When the pump goes off, the water is forced back into the jug by gravity. Several growing units can be hooked up to a large central reservoir and pump to make a large system. The water loss can automatically be replaced using a float valve, similar to the ones used to regulate water in a toilet. Some growers place a second tube near the top of the container which they use as an overflow drain. Another system uses a reservoir above the growing container level. A water timing valve or solenoid valve keeps the water in the reservoir most of the time. When the valve opens, the water fills the growing containers as well as a central chamber which are both at the same height. The growing chambers and the central chamber are attached to each other. The water level is regulated by a float valve and a sump pump. When the water level reaches a certain height, near the top of the pots, the sump pump automatically turns on and the water is pumped back up to the reservoir. One grower used a kiddie pool, timer valve, flower pots, a raised reservoir and a sump pump. He placed the containers in the kiddie pool along with the sump pump and a float valve. When the timer valve opened, the water rushed from the tank to the kiddie pool, flooding the containers. The pump turned on when the water was two inches from the top of the containers and emptied the pool. Only when the valve reopened did the plants receive more water. With this system, growers have a choice of mediums, including sand, gravel, lava, foam or chopped-up rubber. Vermiculite, perlite, and styrofoam are too light to use. The styrofoam and perlite float, and the vermiculite becomes too soggy. The plants' water needs to increase during the lighted part of the daily cycle, so the best time to water is as the light cycle begins. If the medium does not hold enough moisture between waterings, the frequency of waterings is increased. There are a number of companies which manufacture flood systems. Most of the commercially made ones work well, but they tend to be on the expensive side. They are convenient, though. The Drip System Years ago, the most sophisticated commercial greenhouses used drip emitter systems which were considered exotic and sophisticated engineering feats. These days, gardeners can go to any well-equipped nursery and find all of the materials necessary to design and build the most sophisticated drop systems. These units consist of tubing and emitters which regulate the amount of water delivered to each individual container. Several types of systems can be designed using these devices. The easiest system to make is a non-return drain unit. The plants are watered periodically using a diluted nutrient solution. Excess water drains from the containers and out of the system. This system is only practical when there is a drain in the growing area. If each container has a growing tray to catch excess water and the water control valve is adjusted closely, any excess water can be held in the tray and eventually used by the plant or evaporated. Once a gardener gets the hang of it, matching the amount of water delivered to the amount needed is easy to do. One grower developed a drip emitter system which re-uses water by building a wooden frame using 2x4's and covering it with corrugated plastic sheeting. She designed it so that there was a slight slope. The containers were placed on the corrugated plastic, so the water drained along the corrugations into a rain drainage trough, which drained into a 2 or 3 gallon holding tank. The water was pumped from the holding taink back to the reservoir. The water was released from the reservoir using a timer valve. Aerated Water The aerated water system is probably the most complex of the hydroponic systems because it allows for the least margin of error. It should only be used by growers with previous hydroponic experience. The idea of the system is that the plant can grow in water as long as the roots receive adequate amounts of oxygen. To provide the oxygen, an air pump is used to oxygenate the water through bubbling and also by increasing the circulation of the water so that there is more contact with air. The plants can be grown in individual containers, each with its own bubbler or in a single flooded unit in which containers are placed. One grower used a vinyl covered tank he constructed. He placed individual containers that he made into the tank. His containers were made of heavy-duty nylon mesh used by beermakers for soaking hops. This did not prevent water from circulating around the roots. Aerated water systems are easy to build. A small aquarium air pump supplies all the water that is required. An aerator should be connected to the end and a clear channel made in the container for the air. The air channel allows the air to circulate and not disturb the roots. Gravel, lava, or ceramic is used. Nutrient Film Technique The nutrient film technique is so named because the system creates a film of water that is constantly moving around the roots. This technique is used in many commercial greenhouses to cultivate fast growing vegetables such as lettuce without any medium. The plants are supported by collars which hold them in place. This method is unfeasible for marijuana growers. However, it can be modified a bit to create an easy-to-care-for garden. Nursery suppliers sell water mats, which disperse water from a soaker hose to a nylon mat. The plants grow in the bottomless containers which sit on the mat. The medium absorbs water directly from the mat. In order to hold the medium in place, it is placed in a nylon net bag in the container. Marijuana Grower's Handbook - part 10 of 33 "Growing in the Ground" Some growers have the opportunity to grow plants directly in the ground. Many greenhouses are built directly over the earth. Growing directly in the soil has many advantages over container growing. A considerable amount of labor may be eliminated because there is no need to prepare labor-intensive containers with expensive medium. Another advantage is that the plants' needs are met more easily. Before using any greenhouse soil, it is necessary to test it. The pH and fertility of soils vary so much that there are few generalizations that can be made about them. The most important quality of any soil is its texture. Soils which drain well usually are composed of particles of varying size. This creates paths for water to flow and also allows airs pockets to remain even when the soil is saturated. Soils composed of very fine particles, such as mucks and clay, do not drain well. Few air particles are trapped in these soils when they are saturated. When this happens, the roots are unable to obtain oxygen and they weaken when they are attacked by anaerobic bacteria. These soils should be adjusted with sand and organic matter which help give the medium some porosity. Materials suitable for this include sand, compost, composted manure, as well as perlite, lava, gravel, sphagnum moss, styrofoam particles and foam particles. Low lying areas may have a very high water table so that the soils remain saturated most of the time. One way to deal with this problem is to create a series of mounds or raised beds so that the roots are in ground at higher level than the floor level. Once soil nutrient values are determined, adjustments can be made in the soil's fertility. For marijuana, the soil should test high in total Nitrogen, and the medium should test high in Phosphorous and Potassium. This is covered in subsequent files. Growers use several methods to prepare the soil. Some prefer to till the whole area using either a fork, a roto-tiller or a small tractor and plow. The marijuana plant grows both vertical and horizontal roots. The horizontal roots grow from the surface to a depth of 9-18 inches depending on the soil's moisture. They grow closer to the surface of moist soils. The vertical root can stretch down several feet in search of water. In moist soils, the vertical roots may be short, even stunted. Soil with loose texture, sandy soils, and soils high in organic matter may have adequate aeration, porosity, and space for roots and may not have to be tilled at all. Most soils should be dug to a depth of 6-9 inches. The tighter the soil's texture, the deeper it should be filled. If the soil is compacted, it is dug to a depth of two feet. This can be done by plowing and moving the soil in alternate rows and then plowing the newly uncovered soil. Soil texture adjustors such as gypsum are added to the bottom layer of the soil as well as the top layer, but soil amendments such as fertilizers or compst are added only to the top layer, where most of the plant's roots are. Then the soil is moved back into the troughs and the alternate rows are prepared the same way. A variation of this technique is the raised bed. First, the whole area is turned, and then aisles are constructed by digging out the pathways and adding the material to the beds. With the addition of organic soil amendments, the total depth of prepared soil may stretch down 18 inches. Some growers use planting holes rather than tilling the soil. A hole ranging between 1 and 3 feet wide and 1.5 and 3 feet deep is dug at each space where there is to be a plant. The digging can be facilitated using a post hole digger, electric shovel, or even a small backhoe or power hole digger. Once the hole is dug the soil is adjusted with amendments or even replaced with a mix. No matter how the soil is prepared, the groundwater level and the permeability of the lower layers is of utmost importance. Areas with high water tables, or underlying clay or hardpan will not drain well. In either case the harden should be grown in raised beds which allow drainage through the aisles and out of the growing area, rather than relying on downward movement through soil layers. Soils in used greenhouses may be quite imbalanced even if the plants were growing in containers. The soil may have a buildup of mutrient salts, either from runoff or direct application, and pesticides and herbicides may be present. In soils with high water tables, the nutrients and chemicals have nowhere to go, so they dissolve and spread out horizontally as well as vertically, contaminating the soil in surrounding areas. Excess salts can be flushed from the soil by flooding the area with water and letting it drain to the water table. In areas with high water tables, flushing is much more difficult. Trenches are dug around the perimeter of the garden which is then flooded with nutrient-free water. As the water drains into the trenches, it is removed with a pump and transported to another location. Pesticides and herbicides may be much mroe difficult to remove. Soils contaminated with significant amounts of residues may be unsuitable for use with material to be ingested or inhaled. Instead, the garden should be grown in containers using nonindigenous materials. Usually plants are sexed before they are planted into the ground. If the soil showed adequate nutrient values no fertilizer or side dressing will be required for several months. Several growers have used ingenious techniqures to provide their gardens with earthy environments. One grower in Oregon chopped through the concrete floor of his garage to make planting holes. The concrete had been poured over sub-soil so he dug out the holes and replaced the sub-soil with a mixture of composted manure, vermiculite, perlite, worm castings, and other organic ingredients. He has been using the holes for several years. After several crops, he redigs the holes and adds new ingredients to the mix. A grower in Philadelphia lived in a house with a backyard which was cemented over. He constructed a raised bed over the concrete using railroad ties and filled it with a rich topsoil and composted manure mixture, then built his greenhouse over that. The growing bed is about 15 inches deep and the grower reports incredible growth rates. Marijuana Grower's Handbook - part 11 of 33 "Lighting and Lights" Green plants use light for several purposes. The most amazing thing that they can do with it is to use the energy contained in light to make sugar from water and carbon dioxide. This process is called photosynthesis and it provides the basic building block for most life on Earth. Plants convert the sugars they make into starches and then into complex molecules composed of starches, such as cellulose. Amino acids, the building blocks of all proteins, are formed with the addition of nitrogen atoms. Plants also use ligh to regulate their other life processes. As we mentioned earlier, marijuana regulates its flowering based on the number of hours of uniterrupted darkness. (See part 25, Flowering) Sunlight is seen as white light, but is composed of a broadf band of colors which cover the optic spectrum. Plants use red and blue light most efficiently for photosynthesis and to regulate other processes. However, they do use other light colors as well for photosynthesis. In fact, they use every color except green, which they reflect back. (That is why plants appear green; they absorb all the other spectrums except green.) In controlled experiements, plants respond more to the toal amount of light received than to the spectrums in which it was delivered. The best source of light is the sun. It requires no expense, no electricity, and does not draw suspicion. It is brighter than artifical light and is self regulating. Gardeners can use the sun as a primary source of light if they have a large window, skylight, translucent roof, enclosed patio, roof garden, or greenhouse. These gardens may require some supplemental lightning, especially if the light enters from a small area such as a skylight, in order to fill a large area. It is hard to say just how much supplemental light a garden needs. Bright spaces which are lit from unobstructed overhead light such as a greenhouse or a large southern window need no light during the summer but may need artificial light during the winter to supplement the weak sunlight or overcast conditions. Spaces receiving indirect sunlight during the summer may need some supplemental lighting. Light requirements vary by variety. During the growth cycle, most varieties will do well with 1000-1500 lumens per square foot although the plants can usemore lumens, up to 3000, efficiently. Equatorial varieties may develop long internodes (spaces on the stem between the leaves) when grown under less that bright conditions. During flowering, indica varieties can mature well on 2000 lumens. Equatorial varieties require 2500-5000 lumens. Indica-sativa F1 (first generation) hybrids usually do well on 2500-3000 lumens. Some light meters have a foot-candle readout. Thirty-five millimeter cameras that have built-in light meters can also be used. In either case, a sheet of white paper is placed at the point to be measured so it reflects the light most brilliantly. Then the meter is focused entirely on the paper. The camera is set for ASA 100 film and the shutter is set for 1/60 second. A 50 mm or "normal" lens is used. Using the manual mode, the camera is adjusted to the correct f-stop. The conversion chart, 10-1, shows the amount of light hitting the paper. Most growers, for one reason or another, are not able to use natural light to grow marijuana. Instead, they use artificial lights to provide the light energy which plants require to photosynthesize, regulate their metabolism, and ultimately to grow. There are a number of sources of artificial lighting. Cultivators rarely use incandescent or quartz halogen lights. They convert only about 10% of the energy they use to light and are considered inefficient. Chart 10-1: Footcandles +----------------------+----------------------+ | 1/60 Second, ASA 100 | 1/125 Second ASA 100 | +--------+-------------+--------+-------------+ | F-Stop | Footcandles | F-Stop | Footcandles | +--------+-------------+--------+-------------+ | f.4 | 64 | f.4 | 128 | +--------+-------------+--------+-------------+ | f.5.6 | 125 | f.5.6 | 250 | +--------+-------------+--------+-------------+ | f.8 | 250 | f.8 | 500 | +--------+-------------+--------+-------------+ | f.11 | 500 | f.11 | 1000 | +--------+-------------+--------+-------------+ | f.16 | 1000 | f.16 | 2000 | +--------+-------------+--------+-------------+ | f.22 | 2000 | f.22 | 4000 | +--------+-------------+--------+-------------+ On some cameras it is easier to adjust the shutter speed, keeping the f.stop set at f.4 (at ASA 100): +----------------+-------------+ | Shutter Speed | Footcandles | +----------------+-------------+ | 1/60 | 64 | +----------------+-------------+ | 1/125 | 125 | +----------------+-------------+ | 1/250 | 250 | +----------------+-------------+ | 1/500 | 500 | +----------------+-------------+ | 1/1000 | 1000 | +----------------+-------------+ | 1/2000 | 2000 | +----------------+-------------+ FLUORESCENT TUBES Growers have used flurorescent tubes to provide light for many years. They are inexpensive, are easy to set up, and are very effective. Plants grow and bud well under them. They are two to three times as efficient as incandescents. Until recently, fluorescents came mostly in straight lengths of 2, 4, 6, or 8 feet, which were placed in standard reflectors. Now there are many more options for the fluorescent user. One of the most convenient fixtures to use is the screw-in converter for use in incandescent sockets, which come with 8 or 12 inch diameter circular fluorescent tubes. A U-shaped 9 inch screw-in fluorecent is also available. Another convenient fixture is the "light wand", which is a 4 foot, very portable tube. It is not saddled with a cumbersome reflector. Fluorescents come in various spectrums as determined by the type of phosphor with which the surface of the tube is coated. Each phosphor emits a different set of colors. Each tube has a spectrum identification such as "warm white", "cool white", "daylight", or "deluxe cool white" to name a few. This signifies the kind of light the tube produces. For best results, growers use a mixture of tubes which have various shades of white light. Once company manufactures a fluorescent tube which is supposed to reproduce the sun's spectrum. It is called the Vita-Lite and works well. it comes in a more efficient version, the "Power Twist", which uses the same amount of electricity but emits more light because it has a larger surface area. "Gro-Tubes" do not work as well as regular fluorescents even though they produce light mainly in the red and blue spectrums. They produce a lot less light than the other tubes. To maintain a fast growing garden, a minimum of 20 watts of fluorescent light per square foot is required. As long as the plants' other needs are met, the more light that the plants receive, the faster and bushier they will grow. The plants' buds will also be heavier and more developed. Standard straight-tubed fluorescent lamps use 8-10 watts per linear foot. To light a garden, 2 tubes are required for each foot of width. The 8 inch diameter circular tubes use 22 watts, the 12 inch diameter use 32 watts. Using straight tubes, it is possible to fit no more than 4 tubes in each foot of width because of the size of the tubes. A unit using a combination of 8 and 12 inch circular tubes has an input of 54 watts per square foot. Some companies manufacture energy-saving electronic ballasts designed for use with special fluorescent tubes. These units use 39% less electricity and emit 91% of the light of standard tubes. For instance, an Optimizer warm light white 4 foot tube uses 28 watts and emits 2475 lumens. Both standard and VHO ballasts manufactured before 1980 are not recommended. They were insulated using carcinogenic PCB's and they are a danger to your health should they leak. The shape of the fluorescent reflector used determines, to a great extent, how much light the plants receive. Fluorescent tubes emit light from their entire surface so that some of the light is directed at the reflector surfaces. Many fixtures place the tubes very close to each other so that only about 40% of the light is actually transmitted out of the unit. The rest of it is trapped between the tubes or between the tubes and the reflector. This light may as well not be emitted since it is doing no good. A better reflector can be constructed using a wooden frame. Place the tube holders at equal distances from each other at least 4 inches apart. This leaves enough space to construct small mini-reflectors which are angled to reflect the light downward and to seperate the light from the different tubes so that it is not lost in crosscurrents. These mini-reflectors can be made from cardboard or plywood painted white. The units should be no longer than 2.5 feet wide so that they can be manipulated easily. Larger units are hard to move up and down and they make access to the garden difficult, especially when the plants are small, and there is not much vertical space. The frame of the reflector should be covered with reflective material such as aluminum foil so that all of the light is directed to the garden. Fluorescent lights should be placed about 2-4 inches from the tops of the plants. [pH:in Ed's diagram, the reflectors between the lights have a shape similar to this: * * * * * * * * * Sort of a curving V, if you see what I mean.] Growers sometimes use fluorescent lights in innovative ways to supplement the main source of the light. Lights are sometimes placed along the sides of the garden or in the midst of it. One grower used light wands which he hung vertically in the midst of the garden. This unit provided light to the lower parts of the plant which are often shaded. Another grower hung a tube horizontally at plant level between each row. He used no reflector because the tube shined on the plants from ever angle. Lights can be hung at diagonal angles to match the different plants' heights. VERY HIGH OUTPUT (VHO) FLUORESCENTS Standard fluorescents use about 10 watts per linear foot - a 4 foot fluorescent uses 40 watts, an 8 footer 72 watts. VHO tubes use about three times the electricity that standard tubes use, or about 215 watts for an 8 foot tube, and they emit about 2.5 times the light. While they are not quite as efficient as a standard tube, they are often more convenient to use. Two tubes per foot produce the equivalent electricity of 5 standard tubes. [pH:That's what he says. Why one would want the tubes to produce electricity instead of light I will never know.] Only one tube per foot is needed and two tubes emit a very bright light. The banks of tubes are eliminated. VHO tubes come in the same spectrums as standards. They require different ballasts than standards and are available at commercial lighting companies. METAL HALIDE LAMPS Metal halide lamps are probably the most popular lamp used for growing. These are the same type of lamp that are used outdoors as streetlamps or to illuminate sports events. They emit a white light. Metal halide lamps are very convenient to use. They come ready to plug in. The complete unit consists of a lamp (bulb), fixture (reflector) and long cord which plungs into a remote ballast. The fixture and lamp are lightweight and are easy to hang. Only one chain or rope is needed to suspend the fixture, which take up little space, making it easy to gain access to the garden. In an unpublished, controlled experiment, it was observed that marijuana plants responded better to light if the light came from a single point source such as a metal halide, rather than from emissions from a broad area as with fluorescents. Plants growing under metal halides develop quickly into strong plants. Flowering is profuse, with heavier budding than under fluroescents. Lower leaf development was better too, because the light penetrated the top leaves more. Metal halide lamps are hung in two configurations: veritcal and horizontal. The horizontal lamp focuses a higher percent of light on the garden, but it emits 10% less light. Most manufacturers and distributors sell verically hanging metal halides. However, it is worth the effort to find a horizontal unit. In order for a vertical hanging metal halide lamp to deliver light to the garden efficiently, the horizontal light that is emitting must be directed downward or the halide must be placed in the midst of the garden. It only becomes practical to remove the reflector and let the horizontally directed light radiate when the plants have grown a minimum of six feet tall. Reflectors for vertical lamps should be at least as long as the lamp. If a reflector does not cover the lamp completely, some of the light will be lost horizontally. Many firms sell kits with reflectors which do not cover the whole lamp. Reflectors can be modified using thin guage wire such as poultry wire and aluminum foil. A hole is cut out in the middle of the chicken wire frame so that it fits over the wide end of the reflector. Then it is shaped so that it will distribute the light as evenly as possible. Aluminum foil is placed over the poultry wire. (One grower made an outer frame of 1 x 2's which held the poultry wire, metal halide, and foil). Metal halide lamps come in 400, 1000, and 1500 watt sizes. The 1500 watt lamps are not recommended because they have a much shorter life than the other lamps. The 400 watt lamps can easily illuminate a small garden 5 x 5 feet or smaller. These are ideal lights for a small garden. They are also good to brighten up dark spots in the garden. In European nurseries, 400 watt horizontal units are standard. They are attached to the ceiling and placed at even 5 foot intervals so that light from several lamps hits each plant. Each lamp beam diffuses as the vertical distance from the plants may be 6-8 feet, but no light is lost. The beams overlap. No shuttle type device is required. The same method can be used with horizontal 1000 watt lamps and 8 foot intervals. Vertical space should be at least 12 feet. HIGH PRESSURE SODIUM VAPOR LAMPS Sodium vapor lamps emit an orange or amber-looking light. They are the steet lamps that are commonly used these days. These lights look peculiar because they emit a spectrum that is heavily concentrated in the yellow, orange, and red spectrums with only a small amount of blue. They produce about 15% more light than metal halides. They use the same configuration as metal halides: lamp, reflector, and remote ballast. Growers originally used single sodium vapor lamps primarily for flowering because they thought that if the extra yellow and orange light was closer to the sun's spectrum in the fall, when the amount of blue light reaching Earth was limited, the red light would increase flowering or resin production. In another unpublished controlled experiment, a metal halide lamp and a sodium vapor lamp were used as the only sources of light in 2 different systems. The garden under the metal halide matured about a week faster than the garden under the sodium vapors. Resin content seemed about the same. Other growers have reported different results. They claim that the sodium vapor does increase THC and resin production. Plants can be grown under sodium vapor lights as the sole source of illumination. Many growers use sodium vapor lamps in conjunction with metal halides; a typical ratio is 2 halides to 1 sodium. Some growers use metal halides during the growth stages but change to sodium vapor lamps during the harvest cycle. This is not hard to do since both lamps fit in the same reflector. The lamps use different ballasts. High pressure sodium vapor lamps come in 400 and 100 watt configurations with remote ballasts designed specifically for cultivation. Smaller wattages designed for outdoor illumination are available from hardware stores. The small wattage lamps can be used for brightening dark areas of the garden or for hanging between the rows of plants in order to provide bright light below the tops. ACCESSORIES One of the most innovative accessories for lighting is the "Solar Shuttle" and its copies. This device moves a metal halide or sodium vapor lamp across a track 6 feet or longer. Because the lamp is moving, each plant comes directly under its field several times during the growing period. Instead of plants in the center receiving more light than those on the edge, the light is more equally distributed. This type of unit increases the total efficiency of the garden. Garden space can be increased by 15-20% or the lamp can be used to give the existing garden more light. Other units move the lamps over an arc path. The units take various amounts of time to complete a journey - from 40 seconds upward. ELECTRICITY AND LIGHTING At 110-120 volts, a 1000 watt lamp uses about 8.7 amps (watts divided by volts equals amps). Including a 15% margin for safety it can be figured as 10 amps. Many household circuits are rated for 20 or 30 amps. Running 2 lights on a twenty amp circuit taxes it to capacity and is dangerous. If more electricity is required than can be safely supplied on a circuit, new wiring can be installed from the fusebox. All electrical equipment should be grounded. Some growers report that the electrical company's interest was aroused, sometimes innocently, when their electric bill began to spurt. After all, each hour a lamp is on it uses about 1 kilowatt hour. Marijuana Grower's Handbook - part 12 of 33 "Carbon Dioxide" Carbon dioxide (CO2) is a gas which comprises about .03% (or 300 parts per million, "PPM") of the atmosphere. It is not dangerous. it is one of the basic raw materials (water is the other) required for photosynthesis. The plant makes a sugar molecule using light for energy, CO2 which is pulled out of the air, and water, which is pulled up from its roots. Scientists belive that early in the Earth's history the atmosphere contained many times the amount of CO2 it does today. Plants have never lost their ability to process gas at these high rates. In fact, with the Earth's present atmosphere, plant growth is limited. When plants are growing in an enclosed area, there is a limited amount of CO2 for them to use. When the CO2 is used up, the plant's photosynthesis stops. Only as more CO2 is provided can the plant use light to continue the process. Adequate amounts of CO2 may be easily replaced in well-ventilated areas, but increasing the amount of CO2 to .2% (2000 PPM) or 6 times the amount usually found in the atmosphere, can increase growth rate by up to 5 times. For this reason, many commercial nurseries provide a CO2 enriched area for their plants. Luckily, CO2 can be supplied cheaply. At the most organic level, there are many metabolic processes that create CO2. For example, organic gardeners sometimes make compost in the greenhouse. About 1/6 to 1/4 of the pile's starting wet weight is converted to CO2 so that a 200 pound pile contributes 33-50 pounds of carbon to the gas. Carbon makes up about 27% of the weight and volume of the gas and oxygen makes up 73%, so that the total amount of CO2 created is 122 to 185 pounds produced over a 30 day period. Brewers and vintners would do well to ferment their beverages in the greenhouse. Yeast eat the sugars contained in the fermentation mix, released CO2 anf alcohol. The yeast produce quite a bit of CO2, when they are active. One grower living in a rural area has some rabbit hutches in his greenhouse. The rabbits use the oxygen produced by the plants, and in return, release CO2 by breathing. Another grower told me that he is supplying his plants with CO2 by spraying them periodically with seltzer (salt-free soda water), which is water with CO2 dissolved. He claims to double the plants' growth rate. This method is a bit expensive when the plants are large, but economical when they are small. A correspondent used the exhausts from his gas-fired water heater and clothes dryer. To make the area safe of toxic fumes that might be in the exhaust, he built a manually operated shut-off valve so that the spent air could be directed into the growing chamber or up a flue. Before he entered the room he sent any exhausts up the flue and turned on a ventilating fan which drew air out of the room. Growers do not have to become brewers, rabbit farmers, or spray their plants with Canada Dry. There are several economical and convenient ways to give the plants adequate amounts of CO2: using a CO2 generator, which burns natural gas or kerosene, using a CO2 tank with regulator, or by evaporating dry ice. To find out how much CO2 is needed to bring the growing area to the ideal 2000 PPM, multiply the cubic area of the growing room (length x width x height) by .002. The total represents the number of square feet of gas required to reach optimum CO2 range. For instance, a room 13' x 18' x 12' contains 2808 cubic feet: 2808 x .002 equals 5.6 cubic feet of CO2 required. The easiest way to supply the gas is to use a CO2 tank. All the equipment can be built from parts available at a welding suspply store or purchased totally assembled from many growing supply companies. Usually tanks come in 20 and 50 pound sizes, and can be bought or rented. A tank which holds 50 pounds has a gross weight of 170 pounds when filled. A grow room of 500 cubic feet requires 1 cubic foot of CO2 A grow room of 1000 cubic feet requires 2 cubic feet of CO2 A grow room of 5000 cubic feet requires 10 cubic feet of CO2 A grow room of 10,000 cubic feet requires 20 cubic feet of CO2 To regulate dispersal of the gas, a combination flow meter/regulator is required. Together they regulate the flow between 10 and 50 cubic feet per hour. The regulator standardizes the pressure and regulates the number of cubic feet released per hour. A solenoid valve shuts the flow meter on and off as regulated by a multicycle timer, so the valve can be turned on and off several times each day. If the growing room is small, a short-range timer is needed. Most timers are calibrated in 1/2 hour increments, but a short-range timer keeps the valve open only a few minutes. To find out how long the valve should remain open, the numberof cubic feet of gas required (in our example 5.6 feet) is divided by the flow rate. For instance, if the flow rate is 10 cubic feet per hour, 5.6 divided by 10 .56 hours or 3 minutes (.56 X 60 minutes = 33 minutes). At 30 cubic feet per hour, the number of minutes would be .56 divided by 30 X 60 minutes = 11.2 minutes. [pH:Oh me oh my, there's another mistake! The ".56" in the latter equation should be 5.6, guess the people who did the book didn't bother to check his math!] The gas should be replenished ever two hours in a warm, well-lit room when the plants are over 3 feet high if there is no outside ventilation. When the plants are smaller or in a moderately lit room, they do not use the CO2 as fast. With ventilation the gas should be replenished once an hour or more frequently. Some growers have a ventilation fan on a timer in conjunction with the gas. The fan goes off when the gas is injected into the room. A few minutes before the gas is injected into the room, the fan starts and removes the old air. The gas should be released above the plants since the gas is heavier than air and sinks. A good way to disperse the gas is by using inexpensive "soaker hoses", sold in plant nurseries. These soaker hoses have tiny holes in them to let out the CO2. The CO2 tank is placed where it can be removed easily. A hose is run from the regulator unit (where the gas comes out) to the top of the garden. CO2 is cooler and heavier than air and will flow downward, reaching the top of the plants first. Dry ice is CO2 which has been cooled to -109 degrees, at which temperature it becomes a solid. It costs about the same as the gas in tanks. It usually comes in 30 pound blocks which evaporate at the rate of about 7% a day when kept in a freezer. At room temperatures, the gas evaporates considerably faster, probably supplying much more CO2 than is needed by the plants. One grower worked at a packing plant where dry ice was used. Each day he took home a couple of pounds, which fit into his lunch pail. When he came home he put the dry ice in the grow room, where it evaporated over the course of the day. Gas and kerosene generators work by burning hydrocarbons which release heat and create CO2 and water. Each pound of fuel burned produces about 3 pounds of CO2, 1.5 pounds of water and about 21,800 BTU's (British Thermal Units) of heat. Some gases and other fuels may have less energy (BTU's) per pound. The fuel's BTU rating is checked before making calculations. Nursery supply houses sell CO2 generators especially designed for greenhouses, but household style kerosene or gas heaters are also suitable. They need no vent. The CO2 goes directly into the room's atmosphere. Good heaters burn cleanly and completely, leaving no residues, creating no carbon monoxide (a colorless, odorless, poisonous gas). Even so, it is a good idea to shut the heater off and vent the room before entering the space. If a heater is not working correctly, most likely it burns the fuel incompletely, creating an odor. More expensive units have pilots and timers; less expensive models must be adjusted manually. Heaters with polits can be modified to use a solenoid valve and timer. At room temperature, one pound of CO2 equals 8.7 cubic feet. It takes only 1/3 of a pound of kerosene (5.3 ounces) to make a pound of CO2. To calculate the amount of fuel required, the number of cubic feet of gas desired is divided by 8.7 and multiplied by .33. In our case, 5.6 cubic feet divided by 8.7 times .33 equals .21 pounds of fuel. To find out how many ounces this is, multiple .21 times 16 (the number of ounces in a pound) to arrive at a total of 3.3 ounces, a little less than half a cup (4 ounces). 3/5ths ounce provides 1 cubic foot of CO2 1.2 ounces produce 2 cubic feet of CO2 3 ounces produce 5 cubic feet of CO2 6 ounces produce 10 cubic feet of CO2 To find out fuel usage, divide the number of BTU's produced by 21,800. If a generator produces 12,000 BTU's an hour, it is using 12,000 divided by 21,800 or about .55 pounds of fuel per hour. However only .21 pounds are needed. To calculate the number of minutes the generator should be on, the amount of fuel needed is divided by the flow rate and multiplied by 60. In our case, .21 (amount of fuel needed) divided by .55 (flow rate) multiplied by 60 equals 22.9 minutes. The CO2 required for at least one grow room was supplied using gas lamps. The grower said that she thought it was a shame that the fuel was used only for the CO2 and thought her plants would benefit from the additional light. She originally had white gas lamps spaced evenly throughout the garden. She replaced them after the first crop with gas lamps all hooked up to a central LP gas tank. She only had to turn the unit on and light the lamps each day. It shut itself off. She claims the system worked very well. CO2 should be replenished every 3 hours during the light cycle, since it is used up by the plants and leaks from the room into the general atmosphere. Well-ventilated rooms should be replenished more often. It is probably more effective to have a generator or tank releasing CO2 for longer periods at slower rates than for shorter periods of time at higher rates. Marijuana Grower's Handbook - part 13 of 33 "Temperature" Marijuana plants are very hardy and survive over a wide range of temperatures. They can withstand extremely hot weather, up to 120 degrees, as long as they have adequate supplies of water. Cannabis seedlings regularly survive light frost at the beginning of the season. Both high and low temperatures slow marijuana's rate of metabolism and growth. The plants function best in moderate temperatures - between 60 and 85 degrees. As more light is available, the ideal temperature for normal plant growth increases. If plants are given high temperatures and only moderate light, the stems elongate. Conversely, strong light and low temperatures decrease stem elongation. During periods of low light, strong elongation is decreased by lowering the temperature. Night temperatures should be 10-15 degrees lower than daytime temperatures. Temperatures below 50 degrees slow growth of most varieties. When the temperature goes below 40 degrees, the plants may experience some damage and require about 24 hours to resume growth. Low nighttime temperatures may delay or prevent bud maturation. Some equatorial varieties stop growth after a few 40 degree nights. A sunny room or one illuminated by high wattage lamps heats up rapdily. During the winter the heat produced may keep the room comfortable. However the room may get too warm during the summer. Heat rises, so that the temperature is best measured at the plants' height. A room with a 10 foot ceiling may feel uncomfortably warm at head level but be fine for plants 2 feet tall. If the room has a vent or window, an exhaust fan can be used to cool it. Totally enclosed spaces can be cooled using a water conditioner which cools the air by evaporating water. If the room is lit entirely by lamps, the day/night cycle can be reversed so that the heat is generated at night, when it is cooler out. Marijuana is a low-temperature tolerant. Outdoors, seedlings sometimes pierce snow cover, and older plants can withstand short, light frosts. Statistically, more males develop in cold temperatures. However, low temperatures slow down the rate of plant metabolism. Cold floors lower the temperature in containers and medium, slowing germination and growth. Ideally, the medium temperature should be 70 degrees. There are several ways to warm the medium. The floor can be insulated using a thin sheet of styrofoam, foam rubber, wood or newspaper. The best way to insulate a container from a cold floor is to raise the container so that there is an air space between it and the floor. Overhead fans, which circulate the warm air downward from the top of the room also warm the medium. When the plants' roots are kept warm, the rest of the plant can be kept cooler with no damage. Heat cables or heat mats, which use small amounts of electricity, can be used to heat the root area. These are available at nursery supply houses. When watering, tepid water should be used. Cultivators using systems that recirculate water can heat the water with a fish tank heater and thermostat. If the air is cool, 45-60 degrees, the water can be heated to 90 degres. If the air is warm, over 60 degrees, 70 degrees for the water is sufficient. The pipes and medium absorb the water down a bit before it reaches the roots. Gardens using artificial lighting can generate high air temperatures. Each 100 watt metal halide and ballast emits just a little less energy can a 10 amp heater. Several lights can raise the temperature to an intolerable level. In this case a heat exchanger is required. A venting fan or misters can be used to lower temperatures. Misters are not recommended for use around lights. Greenhouses can also get very hot during the summer. If the sun is very bright, opaquing paint may lower the amount of light and heat entering the greenhouse. Fans and cooling mats also help. Cooling mats are fibrous plastic mats which hold moisture. Fans blow air through the mats which lowers the greenhouse temperature. They are most effective in hot dry areas. They are available througn nursery supply houses. Marijuana Grower's Handbook - part 15 of 33 "pH and Water" The pH is the measure of acid-alkalinity balance of a solution. It is measured on a scale of 0-14, with 0 being the most acid, 7 being neutral, and 14 being most alkaline. [pH:In case you're wondering, I'm a total 0!] Most nutrients the plants use are soluble only in a limited range of acidity, between about 6 to about 7.5, neutral. Should the water become too acidic or alkaline, the nutrients dissolved in the water become too acidic or alkaline, the nutrients dissolved in the water precipitate and become unavailable to the plants. When the nutrients are locked up, plant growth is slowed. Typically, a plant growing in an environment with a low pH will be very small, often growing only a few inches in several months. Plants growing in a high pH environment will look pale and sickly and also have stunted growth. All water has a pH which can be measured using aquarium or garden pH chemical reagent test kits or a pH meter. All of these items are available at local stores and are easy to use. Water is pH-adjusted after nutrients are added, since nutrients affect the pH. Once the water is tested it should be adjusted if it does not fall within the pH range of 6 to 7. Ideally the range should be about 6.2-6.8. Hydroponic supply companies sell measured adjusters which are very convenient and highly recommended. The water-nutrient solution can be adjusted using common household chemicals. Water which is too acidic can be neutralized using bicarbonate of soda, wood ash, or by using a solution of lime in the medium. Water which is too alkaline can be adjusted using nitric acid, sulfuric acid, citric acid (Vitamin C) or vinegar. The water is adjusted using small increments of chemicals. Once a standard measure of how much chemical is needed to adjust the water, the process becomes fast and easy to do. Plants affect the pH of the water solution as they remove various nutrients which they use. Microbes growing in the medium also change the pH. For this reason growers check and adjust the pH periodically, about once every two weeks. The pH of water out of the tap may change with the season so it is a good idea to test it periodically. Some gardeners let tap water sit for a day so that the chlorine evaporates. They believe that chlorine is harmful to plants. The pH of the planting medium affects the pH of the liquid in solution. Medium should be adjusted so that it tests between 6.2-6.8. This is done before the containers are filled so that the medium could be adjusted in bulk. Approximately 1-2 lbs. of dolomitic limestone raises the pH of 100 gallons (4.5-9 grams per gallon) of soil 1 point. Gypsum can be used to lower the pH of soil or medium. Both limestone and gypmsum have limited solubility. There are many forms of limestone which have various effectiveness depending on their chemistry. Each has a rating on the package. Marijuana Grower's Handbook - part 14 of 33 "Air and Humidity" Besides temperatures and CO2 content, air has other qualities including dust content, electrical charge and humidity. Dust "Dust" is actually composed of many different-sized solid and liquid particles which float in the gaseous soup. The particles include organic fibers, hair, other animal and vegetable particles, bacteria, viruses, smoke and odoriferous liquid particles such as essential oils, and water-soluble condensates. Virtually all of the particles have a positive electrical charge, which means that they are missing an electron, and they float (due to electrical charge) through various passing gases. The dust content of the air affects the efficiency of the plant's ability to photosynthesize. Although floating dust may block a small amount of light, dust which has precipitated on leaves may block large amounts. Furthermore, the dust clogs the pores through which plants transpire. Dust can easily be washedoff leaves using a fine mist spray. Water must be prevented from touching and shattering the hot glass of the lights. Negative Ions in unindustrialized verdant areas and near large bodies of water, the air is negatively charged, that is, there are electrons floating in the air unattached to atoms or molecules. In industrialized areas or very dry regions, the air is positively charged; there are atoms and molecules missing electrons. Some researchers claim that the air's electrical charge affects plant growth (and also animal behavior). They claim that plants in a positively charged environment grow slower than those in a negatively charged area. Regardless of the controversy regarding growth and the air's electrical charge, the presence of negative ions creates some readily observable effects. Odors are characteristic of positively charged particles floating in the air. A surplus of negative ions causes the particles to precipitate so that there are no odors. With enough negative ions, a room filled with pungent, flowering sinsemilla is odorless. Spaces with a "surplus" negative ion charge have clean, fresh smelling air. Falling water, which generates negative ions, characteristically creates refreshing air. Dust particles are precipitated so that there are fewer bacteria and fungus spores floating in the air, as well as much less dust in general. This lowers the chance of infection. Many firms manufacture "Negative Ion Generators", "Ionizers", and "Ion Fountains", which disperse large quantities of negative ions into the atmosphere. These units are inexpensive, safe and recommended for all growing areas. Ion generators precipitate particles floating in the air. With most generators, the precipitating particles land within a radius of two feet of the point of dispersal, collecting quickly and developing into a thick film of grime. Newspaper is placed around the unit so that the space does not get soiled. Some newer units have a precipitator which collects dust on a charged plate instead of the other surrounding surfaces. This plate can be rougly simulated by grounding a sheet a aluminum foil. To ground foil, either attach it directly to a metal plumbing line or grounding box; for convenience, the foil can be held with an alligator clip attacked to the electrical wire, which is attached to the grounding source. As the foil gets soiled, it is replaced. Humidity Cannabis grows best in a mildly humid environment: a relative humidy of 40-60 percent. Plants growing in drier areas may experience chronic wilt and necrosis of the leaf tips. Plants growing in a wetter environment usually experience fewer problms; however, the buds are more susceptible to molds which can attack a garden overnight and ruin a crop. Growers are rarely faced with too dry a growing area. Since the space is enclosed, water which is evaporated or transpired by the plants increases the humidity considerably. If there is no ventilation, a large space may reach saturation level within a few days. Smaller spaces usually do not have this buildup because there is usually enough air movement to dissipate the humdity. The solution may be as easy as opening a window. A small ventilation fan can move quite a bit of air out of a space and may be a convenient way of solving the problem. Humidity may be removed using a dehumidifier in gardens without access to convenient ventilation. Dehumidifiers work the same way a refrigerator does except that instead of cooling a space, a series of tubes is cooled causing atmospheric water to condense. The smallest dehumidifiers (which can dry out a large space) use about 15 amps. Usually the dehumidifier needs to run only a few hours a day. If the plant regimen includes a dark cycle, then the dehumidifier can be run when the lights are off, to ease the electrical load. Air Circulation A close inspection of a marijuana leaf reveals many tiny hairs and a rough surface. Combined, these trap air and create a micro-environment around the plant. The trapped air contains more humidity and oxygen and is warmer, which differs significantly in the composition and temperature from the surrounding atmosphere. The plant uses CO2 so there is less left in the air surrounding the leaf. Marijuana depends on air currents to move this air and renew the micro-environment. If the air is not moved vigorously, the growth rate slows, since the micro-environment becomes CO2 depleted. Plants develop firm, sturdy stems as the result of environmental stresses. Outdoors, the plants sway with the wind, causing tiny breaks in the stem. These are quickly repaired bythe plant's reinforcing the original area and leaving it stronger than it was originally. Indoors, plants don't usually need to cope with these stresses so their stems grow weak unless the plants receive a breeze or are shaken by the stems daily. A steady air flow form the outdoor ventilation may be enough to keep the air moving. If this is not available, a revolving fan placed several feet from the nearest plant or a slow-moving overhead fan can solve the problem. Screen all air intake fans to prevent pests. Marijuana Grower's Handbook - part 16 of 33 "Nutrients" Marijuana requires a total of 14 nutrients which it obtains through its roots. Nitrogen (N), Phosophorous (P), and Potassium (K) are called the macro-nutrients because they are used in large quantities by the plant. The percentages of N, P, and K are always listed in the same order on fertilizer packages. Calcium (Ca), sulfur (S), and magnesium (Mg) are also required by the plants in fairly large quantities. These are often called the secondary nutrients. Smaller amounts of iron (Fe), zinc (Zn), manganese (Mn), boron (B), cobalt (Co), copper (Cu), molybdenum (Mo) and chlorine (Cl) are also needed. These are called micro-nutrients. [pH:And you thought chemistry wasn't good for anything!] Marijuana requires more N before flowering than later in its cycle. When it begins to flowe, marijuana's use of P increases. Potassium requirements increase after plants are fertilized as a result of seed production. Plants which are being grown in soil mixes or mixes with nutrients added such as compost, manure or time-releasing fertilizers may need no additional fertilizing or only supplemental amounts of the plants begin to show deficiencies. The two easiest and most reliable ways to meet the plant's needs are to use a prepared hydroponic fertilizer or an organic water-soluble fertilizer. Hydroponic fertilizers are blended as complete balanced formulas. Most non-hydroponic fertilizers usually contain only the macronutrients (N, P, and K). Organic fertilizers such as fish emulsion and other blends contain trace elements which are found in the organic matter from which they are derived. Most indoor plant fertilizers are water-soluble. A few of them are time-release formulas which are mixed into the medium as it is being prepared. Plants grown in soil mixes can usually get along using regular fertilizers but plants grown in prepared soilless mixes definitely require micronutrients. As the seeds germinate they are given a nutrient solution high in N such as a 20-10-10 or 17-10-12. These are just two possible formulas; any with a high proportion of N will do. Formulas which are not especially high in N can be used and supplemented with a high N ferilizer such as fish emulsion (which may create an odor) or the Sudbury X component fertilizer which is listed 44-0-0. Urine is also very high in N and is easily absorbed by the plants. It should be diluted to one cup urine per gallon of water. The plants should be kept on a high N fertilizer regimen until they are put into the flowering regimen. During the flowering cycle, the plants do best with a formula lower in N and higher in P, which promotes bloom. A fertilizer such as 5-20-10 or 10-19-12 will do. (Once again, these are typical formulas, similar ones will do). Growers who make their own nutrient mixes based on parts per million of nutrient generally use the following formulas. Chart 15-1: Nutrient/Water Solution In Parts Per Million (PPM) +-----------------------------------+---------+---------+---------+ | | N | P | K | +-----------------------------------+---------+---------+---------+ | Germination - 15 to 20 days | 110-150 | 70-100 | 50-75 | +-----------------------------------+---------+---------+---------+ | Fast Growth | 200-250 | 60-80 | 150-200 | +-----------------------------------+---------+---------+---------+ | Pre-Flowering | 70-100 | 100-150 | 75-100 | | 2 weeks before turning light down | | | | +-----------------------------------+---------+---------+---------+ | Flowering | 0-50 | 100-150 | 50-75 | +-----------------------------------+---------+---------+---------+ | Seeding - fertilized flowers | 100-200 | 70-100 | 100-150 | +-----------------------------------+---------+---------+---------+ Plants can be grown using a nutrient solution containing no N for the last 10 days. Many of the larger leaves yellow and wither as the N migrates from the old to the new growth. The buds are less green and have less of a minty (chlorophyll) taste. Many cultivators use several brands and formulas of fertilizer. They either mix them together in solution or switch brands each feeding. Plant N requirements vary by weather as well as growth cycle. Plants growing under hot conditions are given 10-20% less N or else they tend to elongate and to grow thinner, weaker stalks. Plants in a cool or cold regimen may be given 10-20% more N. More N is given under high light conditions, less is used under low light conditions. Organic growers can make "teas" from organic nutrients by soaking them in water. Organic nutrients usually contain micronutrients as well as the primary ones. Manures and blood meal are among the most popular organic teas, but other organic sources of nutrients include urine, which may be the best source for N, as well as blood meal and tankage. Organic fertilizers vary in their formulas. The exact formula is usually listed on the label. Here is a list of common organic fertilizers which can be used to make teas: Chart 15-2: Organic Fertilizers +----------------+-----+------+------+---------------------------------+ | Fertilizer | N | P | K | Remarks | | Bloodmeal | 15 | 1.3 | .7 | Releases nutrients easily | | Cow manure | 1.5 | .85 | 1.75 | The classic tea. Well- | | (dried) | | | | balanced formula. Medium | | | | | | availability. | +----------------+-----+------+------+---------------------------------+ | Dried blood | 13 | 3 | 0 | Nutrients dissolve easier | | | | | | than bloodmeal | +----------------+-----+------+------+---------------------------------+ | Chicken manure | 3.5 | 1.5 | .85 | Excellent nutrients | +----------------+-----+------+------+---------------------------------+ | Wood ashes | 0 | 1.5 | 7 | Water-soluble. Very alkaline | | | | | | except with acid wood such | | | | | | as walnut | +----------------+-----+------+------+---------------------------------+ | Granite dust | 0 | 0 | 5 | Dissolves slowly | +----------------+-----+------+------+---------------------------------+ | Rock phosphate | 0 | 35 | 0 | Dissolves gradually | | (phosphorous) | | | | | +----------------+-----+------+------+---------------------------------+ | Urine (human, | .5 | .003 | .003 | N immediately available | | fresh) | | | | | +----------------+-----+------+------+---------------------------------+ Commercial water-soluble fertilizers are available. Fish emulsion fertilizer comes in 5-1-1 and 5-2-2 formulas and has been used by satisfied growers for years. A grower cannot go wrong changing hydroponic water/nutrient solutions at least once a month. Once every two weeks is even better. The old solution could be measured, reformulated, supplemented and re-used; unless large amounts of fertilizer are used, such as in a large commercial greenhouse, it is not worth the effort. The old solution may have many nutrients left, but it may be unbalanced since the plants have drawn specific chemicals. The water can be used to water houseplants or an outdoor garden, or to enrich a compost pile. Experienced growers fertilize by eyeing the plants and trying to determine their needs when minor symptoms of deficiencies become apparent. If the nutrient added cures the deficiency, the plant usually responds in apparent ways within one or two days. First the spread of the symptom stops. With some minerals, plant parts that were not too badly damaged begin to repair themselves. Plant parts which were slightly discolored may return to normal. Plant parts which were severely damaged or suffered from necrosis do not recover. The most dramatic changes usually appear in new growth. These parts grow normally. A grower can tell just by plant parts which part grew before deficiencies were corrected. [pH:What's in yer nuggets? Parts. Plant parts. Processed plant parts. HAHAHAHAHAHAHA] Fertilizers should be applied on the low side of recommended rates. Overdoses quickly (within hours) result in wilting and then death. The symptoms are a sudden wilt with leaves curled under. To save plants suffering from toxic overdoses of nutrients, plain water is run through systems to wash out the medium. Gardens with drainage can be cared for using a method commercial nurseries employ. The plants are watered each time with a dilute nutrient/water solution, usually 20-25% of full strength. Excess water runs off. While this method uses more water and nutrients than other techniques, it is easy to set up and maintain. When nutrient deficiencies occur, especially multiple or micronutrient deficiencies, there is a good chance that the minerals are locked up (precipitated) because of pH. [pH:That's not very fair, I wasn't even there!] Rather than just adding more nutrients, the pH must be checked first. If needed, the pH must be changed by adjusting the water. If the pH is too high, the water is made a lower pH than it would ordinarily be; if too low the water is made a higher pH. To get nutrients to the plant parts immediately, a dilute foliar spray is used. If the plant does not respond to the foliar spray, it is being treated with the wrong nutrient. NUTRIENTS Nitrogen (N) Marijuana uses more N than any other nutrient. It is used in the manufacture of chlorophyll. N migrates from old growth to new, so that a shortage is likely to cause first pale green leaves and then the yellowing and withering of the lowers leaves as the nitrogen travels to new buds. Other deficiency symptoms include smaller leaves, slow growth and a sparse rather than bushy profile. N-deficient plants respond quickly to fertilization. Within a day or two, pale leaves become greener and the rate and size of new growth increases. Good water-soluble sources of nitrogen include most indoor and hydroponic fertizliers, fish emulsion, and urine, along with teas made from manures, dried blood or bloodmeal. There are many organic additives which release N over a period of time that can be added to the medium at the time of planting. These include manures, blood, cottonseed meal, hair, fur, or tankage. Phosphorous (P) P is used by plants in the transfer of light energy to chemical compounds. It is also used in large quantities for root growth and flowering. Marijuana uses P mostly during early growth and flowering. Fertilizers and nutrient mixes usually supply adequate amounts of P during growth stages so plants usually do not experience a deficiency. Rock phosphate and bone meal are the organic fertilizers usually recommended for P deficiency. However they release the mineral slowly, and are more suited to outdoor gardening than indoors. They can be added to medium to supplement soluble fertilizers. P-devicient plants have small dark green leaves, with red stems and red veins. The tips of lower leaves sometimes die. Eventually the entire lower leaves yellow and die. Fertilization affects only new growth. Marijuana uses large quantities of P during flowering. Many fertilizer manufacturers sell mixes high in P specifically for blooming plants. Potassium (K) K is used by plants to regulate carbohydrate metabolism, chlorophyll synthesis, and protein synthesis as well as to provide resistance to disease. Adequate amounts of K result in strong, sturdy stems while slightly deficient plants often grow taller, thinner stems. Plants producing seed use large amounts of K. Breeding plants can be given K supplements to assure well-developed seed. Symptoms of greater deficiencies are more apparent on the sun leaves (the large lower leaves). Necrotic patches are found on the leaf tips and then in patches throughout the leaf. The leaves also look pale green. Stems and flowers on some plants turn deep red or purple as a result of K deficiencies. However, red stems are a genetic characteristic of some plants so this symptom is not foolproof. Outdoors, a cold spell can precipitate K and make it unavailable to the plants, so that almost overnight the flowers and stems turn purple. K deficiency can be treated with any high-K fertilizer. Old growth does not absorb the nutrient and will not be affected. However, the new growth will show no signs of deficiency within 2 weeks. For faster results the fetilizer can be used as a foliar spray. K deficiency does not seem to be a crucial problem. Except for the few symptoms, plants do not seem to be affected by it. Calcium (Ca) Ca is used during cell splitting, and to build the cell membranes. Marijuana also stores "excess" Ca for reasons unknown. I have never seen a case of Ca deficiency in cannabis. Soils and fertilizers usually contain adequate amounts. It should be added to planting mixes when they are being formulated at the rate of 1 tablespoon per gallon or 1/2 cup per cubic foot of medium. Sulfur (S) S is used by the plant to help regulate metabolism, and as a constituent of some vitamins, amino acids and proteins. It is plentiful in soil and hydroponic mixes. S deficiencies are rare. First, new growth yellows and the entire plant pales. s deficiencies are easily solved using Epsom salts at the rate of 1 tablespoon per gallon of water. Magnesium (Mg) Mg is the central atom in chlorophyll and is also used in production of carbohydrates. (Chlorophyll looks just like hemoglobin in blood, but has a Mg atom. Hemoglobin has an Fe atom). In potted plants, Mg deficiency is fairly common, since many otherwise well-balanced fertilizers do not contain it. Deficiency symptoms start on the lower leaves which turn yellow, leaving only the veins green. The leaves curl up and die along the tips and edges. Growing shoots are pale green and, as the condition continues, turn almost white. Mg deficiency is easily treated using Epsom salts (MgSO4) at the rate of 1 tablespoon per gallon of water. For faster results, a foliar spray is used. Once Mg deficiency occurs, Epsom salts should be added to the solution each time it is changed. Dolomitic limestone contains large amounts of Mg. Iron (Fe) Fe deficiency is not uncommon. The growing shoots are pale or white, leaving only dark green veins. The symptoms appear similar to Mg deficiencies but Fe deficiencies do not affect the lower leaves. Fe deficiencies are often the result of acid-alkalinity imbalances. Fe deficiencies sometimes occur together with zinc (Zn) and manganese (Mn) deficiencies so that several symptoms appear simultaneously. Deficiencies can be corrected by adjusting the pH, adding rusty water to the medium, or using a commercial supplement. Fe supplements are sold alone or in a mix combined with Zn and Mn. To prevent deficiencies, some growers add a few rusting nails to each container. One grower using a reservoir system added a pound of nails to the holding tank. The nails added Fe to the nutrient solution as they rusted. Dilute foliar sprays can be used to treat deficiencies. Manganese (Mn) Symptoms of Mn deficiency include yellowing and dying of tissue between veins, first appearing on new growth and then throughout the plant. Deficiencies are solved using an Fe-Zn-Mn supplement. Zinc (Zn) Zn deficiency is noted first as yellowing and necrosis of older leaf margins and tips and then as twisted, curled new growth. Treatment with a Fe-Zn-Mn supplement quickly relieves symptoms. A foliar spray speeds the nutrients to the leaf tissue. Boron (B) B deficiency is uncommon and does not usually occur indoors. Symptoms of B deficiency start at the growing tips, which turn grey or brown and then die. This spreads to the lateral shoots. A B deficiency (pH:A, B, deficient C!) is treated by using 1/2 teaspoon boric acid, available in pharmacies, added to a gallon of water. One treatment is usually sufficient. Molybdenum (Mo) Mo is used by plants in the conversion of N to forms that the plant can use. It is also a consituent of some enzymes. Deficiency is unusual indoors. Symptoms start with paleness, then yellowing of middle leaves which progress to the new shoots and growing tips, which grow twisted. The early symptoms almost mimic N deficiency. Treatment with N may temporarily relieve the symptoms but they return within a few weeks. Mo is included in hydroponic fertilizers and in some trace element mixes. It can be used as a foliar spray. Copper (Cu) Cu is used by plants in the transfer of electrical charges which are manipulated by the plant to absorb nutrients and water. It is also used in the regulation of water content and is a constituent of some enzymes. Cu deficiencies are rare and mimic symptoms of overfertilization. The leaves are limp and turn under at the edges. Tips and edges of the leaves may die and whole plant looks wilted. A fungicide, copper sulfate, (CuSO$) can be used as a foliar spray to relieve the deficiency. NUTRIENT ADDITIVES Various additives are often suggested to boost the nutrient value of the water/nutrient solution. Here are some of them: WETTING AGENTS. Water holds together through surface tension, preventing it from dispersing easily over dry surfaces. Wetting agents decrease the surface tension and allow the water to easily penetrate evenly throughout the medium preventing dry spots. Wetting agents are helpful when they are used with fresh medium and as an occasional additive. Wetting agents should not be used on a regular basis. They may interfere with plants' ability to grow root hairs, which are ordinarily found on the roots. They are available at most plant nurseries. SEAWEED. Washed, ground seaweed contains many trace elements and minerals used by plants. It may also contain some hormones or organic nutrients not yet identified. KELP. Kelp seems to be similar to seaweed in nutrient value. Proponents claim that it has other, as yet undefined organic chemicals that boost plant growth. SEA WATER. Salt water contains many trace elements and organic compounds. Some hydroponists claim that adding 5-10% sea water to the nutrient solution prevents trace element problems. It may be risky. DEFICIENCIES OF NUTRIENT ELEMENTS IN MARIJUANA Suspected Element +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Symptoms | N | P | K | Mg | Fe | Cu | Zn | B | Mo | Mn| Over | | | | | | | | | | | | |Fertil| +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Yellowing of: | | | | | | | | | | | | | | | | | | | | | | | | | | Younger leaves | | | | | X | | | | | X | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Middle leaves | | | | | | | | | X | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Older leaves | X | | X | X | | | X | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Between veins | | | | X | | | | | | X | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Old leaves drop | X | | | | | | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Leaf Curl Over | | | | X | | | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Leaf Curl Under | | | X | | | X | | | | | X | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Leaf tips burn | | | | | | | | | | | | | | | | | | | | | | | | | | Younger leaves | | | | | | | | X | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Older leaves | X | | | | | | X | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Young leaves wrinkle | | | | | | | | | | | | | and curl | | | X | | | | X | X | X | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Necrosis | | | X | X | X | | X | | | X | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Leaf growth stunted | X | X | | | | | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Dark green/purplish | | | | | | | | | | | | | leaves and stems | | X | | | | | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Pale green leaf color| X | | | | | | | | X | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Mottling | | | | | | | X | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Spindly | X | | | | | | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Soft stems | X | | X | | | | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Hard/brittle stems | | X | X | | | | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Growing tips die | | | X | | | | | X | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Stunted root growth | | X | | | | | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ | Wilting | | | | | | X | | | | | | +----------------------+---+---+---+----+----+----+----+---+----+---+------+ Marijuana Grower's Handbook - part 17 of 33 "Novel Gardens" Many people who would like to grow their own think that they don't have the space. There are novel techniques that people can use to grow grass anywhere. Even people with only a closet, crawl space or just a shelf can grow their own. The smallest space that can be used is a shelf 15-24 inches high. First, the space should be prepared as any other garden by making it reflective, using flat white paint, the dull side of aluminum foil, or white plastic. Fluorescents are the easiest and best way to illuminate the space. About twenty watts per square foot are used, or two tubes per foot of width. VHO fluorescents can be used to deliver more light to the system. Plants can be started in 6 ounce cups or 8 to 16 ounce milk cartons placed in trays for easier handling. With a shelf of 3 feet or higher, plants can be grown in larger containers such as 4 to 6 inch pots, half gallon milk containers trimmed to hold only a quart. The plants can be grown vertically only, as they normally grow, or moved to a horizontal position so that the main stem runs parallel to the light tubes. The plants' new growth will immediately face upwards towards the light. One gardener used an attic space only 4 feet tall. She let the plants grow until they reached 3 feet and then turned them on their side. They used more floor space so she opened up a second bank of lights. At maturity, the plants were 3.5 feet long and 2.5 feet tall. Another grower turned his basement with an 8 foot ceiling into a duplex growing chamber. Each unit had 3 foot tall plants. If the plants are to be turned horizontally, then they are best grown in plastic bags or styrofoam cups so that they can be watered easily in their new positions. After being turned on the side, a hole is cut in the new top so the plants can be watered easily. Some growers have wall space without much depth. This space can be converted to a growing area very easily. The space is painted white and a curtain is made so that the space is seperated from the surrounding environment; this will keep light in and offers protection from nosey guests. The fluorescents should be placed so that they form a bank facing the plants. Although the plants naturally spread out, their depth or width can be controlled by training them using stakes or chicken wire placed on a frame. Wire or plastic netting is attached to the walls so that there is at least a 1 inch space between the wire and the wall. Some people build a frame out of 2x4's. Twist ties are used to hold the branches to the frame. Additional light can be supplied by placing a fluorescent unit on either end of the garden or along its length. Growers who have a little more space for their garden, with a minimum width of 1 or 2 feet, can grow plants without training them. Fluorescent lights can be used to light the garden by hanging the light fixture from the top. All sides should be covered with reflective material. A metal halide lamp mounted on a movable apparatus will help the plants grow even faster so that the entire garden is illuminated several times during each light cycle. Some people can spare only a small closet. Closets usually are designed in one of two shapes: square or long and rectangular. In any closet up to six feet long the simplest way to grow is by painting the inside of the closet white and hanging a metal halide light from the ceiling. Closets with dimensions of 5x5 or less need only a 400 watt metal halide although they can accomodate 1000 watt lamps. Larger areas need at least two 400 watt halide lamps. Thin, rectangular closets are served best by a metal halide unit mounted on a solar shuttle type device. A fluorescent light unit hung from above the garden also works well. Additional fluorescent tubes can be used to supplement the top lights. It is convenient to mount them on either end of the hanging fixture if the closet is long enough so that they do not use potential growing space. A closet 2 feet by 7 feet might be illuminated by a 400 watt metal halide on a track, two 6 foot long VHOs or 4 regular fluorescent tubes hung from the ceiling. A grower might also use 14 screw-in 8 inch circular reflectors mounted on two 2x4s and hung above the garden. About 8 combination 8 and 12 inch circular fixtures will also light the area. As the plants grow taller, fluorescent lit gardens will respond to fluorescent tubes placed on the sides of the garden below the tops of the plants. This light wll help lower buds develop. One of the main problems inherent in the nature of small gardens is the lack of ventilation and CO2. For good growth rates the air should be enriched with CO2 or provided with a fan for ventilation. Marijuana Grower's Handbook - part 18 of 33 "Containers" To save space, plants can be germinated in small containers and transplanted to progressively larger ones. Seeds can be germinated in 2 x 1 inch trays or in peat pellets and remain in these containers for about one week. Four inch diameter containers can hold the plants for 2 to 3 weeks without inhibiting growth. Styrofoam cups weighted at the bottom with sand or gravel so they don't tip over are convenient germinating containers. If plants are to be germinated at one location and then moved to another location, styrofoam and other lightweight plastic cups are ideal containers. Six ounce cups hold plants for about 7-10 days after germination. Sixteen ounce cups hold plants 10-20 days, as long as the plants receive frequent water replenishments. Half gallon containers can support plants for 25-40 days. Plants probably grow a bit faster without being transplanted. However, the saving in space for a multi-crop system or even a multi-light system more than compensates for the loss in growth rate. Figure that each transplanting costs the plants 3-4 days of growth. Growers using a 2 light system need to use only one lamp for the first 4-6 weeks the plants are growing. Multi-crop gardens need to use only a fraction of the space for the first 3 to 8 weeks after germination. Some growers sex the plants before either the first or second transplanting. They find it easier to control the light-darkness cycle in a small space. Another crop's flowering cycle may coincide with the seedlings. To sex the small plants, only a small area is required in the grow room. A good rule of thumb is that for each two feet of growth, a half gallon of growing medium is required in a garden in which fertilizers are supplied throughout the growing period. A 2 foot plant requires a 1/2 gallon container, a 5 foot plant uses a 2.5 gallon container and a 10 foot plant requires a 5 gallon unit. Of course, plants' width or depth varies too, so these are approximations. Certainly there is no harm done in growing a plant in a container larger than is required. However, growing plants in containers which are too small delays growth or may even stunt the plants. Plants growing in soil or compost-based mediums do better in slightly larger containers. A rule of thumb for them is a 3/4 gallon medium for each foot of growth. A 5 foot plant requires a 3 and 3/4 gallon container. One grower wrote "I never use more than 4 gallon containers and have grown plants to 12 feet high with no signs of deficiencies. I was able to water at 2-3 day intervals. My 3 month old plants under light were in 1/2 gallon containers with and without wicks." This grower always uses small (1/2 gallon) containers for his spring greenhouse crop. A plant growing in an organic-based medium such as soil-compost-manure and additives needs no fertilization if it is given a large enough container. For a five month growing season, plants in a rich mixture require 1 to 1.5 gallons medium per foot. A 5 foot plant requires a container holding 5-7.5 gallons. Containers should have a slight graduation so that plants and medium can slide out easily. Plastic containers or pots are the most convenient to use. They are lightweight, do not break and are inert. Metal containers react with the nutrients in the solution. Plastic bags are convenient containers. Grow bags have a square bottom so that they balance easily. However growers use all kinds of plastic bags for cultivation. Fiber containers are also popular. They are inexpensive, last several growing seasons and are easy to dispose of. Marijuana Grower's Handbook - part 19 of 33 "When to Plant" Marijuana growers using only artificial light can start at any time since the grower determines the plant's environment and stimulates seasonal variations by adjusting the light/darkness periods. Gardeners using natural light either as a primary or secondary source must take the seasons into account. They plant in the spring - from April through June. These plants will be harvested between September and November and no artificial light may be needed as long as there is plenty of direct sunshine. Supplemental artificial light may help the plants to maturity in the fall, when the sun's intensity declines and there are overcast days. The angle of the sun's path changes over the season too. Areas may receive indirect sun during part of the growing season. In overcast areas, and even sunny places receiving direct sunlight, 4-6 hours of supplemental metal halide light during the brightest part of the day is all that is needed during September/October to help the buds mature. One lamp will cover about 100 square feet or an area 10 by 10 feet. Growers using natural light are not restricted to one season. It is feasible to grow 3 or 4 crops a year using supplemental light. In early October, before the plants are harvested, seeds are started in a seperate area. Since little room is needed for the first few weeks, they can be germinated on a shelf. In addition to natural light, the plants should get a minimum of 6 hours of artificial light per day at the rate of about 10 watts per square foot. For fastest growth, the plants should receive 24 hours of light a day. Seedlings may receive light only during normal day light hours except that they require an interruption of the night cycle so they do not go into the flowering stage prematurely. If metal halide lamps are being used, a seperate light system should be installed with incandescent or fluorescent lights on a timer so that the seedlings do not have a long period of uninterrupted darkness. One 60 watt incandescent bulb or one 22 watt fluorescent tube is used per square yard (3 by 3 feet). The bulbs can be flashed on for a few minutes using a multi-cycle timer during the middle of the dark period. Gardeners with large spaces sometimes stagger the timing of the night lights. Incandescent bulbs are not very effecient, but they provide enough light to prevent flowering, they are easy and inexpensive to set up and maintain, and they light up almost immediately. In addition, they emit a high percentage of red light, which is part of the spectrum used by plants to regulate photoperiod responses.. Metal halides require about 10 minutes to attain full brightness. Metal halide ballasts wear out faster when they are turned on and off a lot, so it is cheaper to flash incandescents. In late December, the incandescents are turned off so that they no longer interrupt the night cycle. Within a week or two the plants will begin to flower. They will be ready to harvest in 6 or 8 weeks. At the same time that the incandescents are turned off the winter crop, seeds are started for the spring crop. They are kept on the interrupted night regimen until late winter, around March 1-10. The plants will begin to flower and be ready in late May and early June. The spring crop should be planted with short season plants so that they do not revert back to vegetative growth as the days get longer. Long season varieties are more likely to revert. After the flowers are formed, the spring crop plants will revert back to vegetative growth. New leaves will appear and the plant will show renewed vigor. The plant can be harvested again in the fall, or new seds can be germinated for the fall crop. One grower reported that he makes full use of his greenhouse. He starts his plants indoors in late November and starts the flowering cycle in the beginning of Februaru. The plants are ripe by the end of April, then he lets the plants go back into vegetative growth for a month and a half. Then he starts to shade them again and harvests in late August. Next he puts out new, month-old, foot-high plants. He lets them grow under natural light, but breaks the darkness cycle using incandescent lights. In mid-September he shuts the lights off, and the plants mature in early November. Marijuana Grower's Handbook - part 20 of 33 "Planting" Growers usually figure that 1/4 - 1/3 of the seeds they plant reach maturity. Usually 40-50% of the plants are male. The best females are chosen for continued growth during early growth but after the plants have indicated. Most fresh seeds have a very high germination rate, usually about 95%. However, older seeds (more than 2 or 3 years old) or seeds imported from foreign countries where they undergo stress during curing, may not fare so well. They have a higher percentage of weak plants and they are subject to disease. Sometimes virtually all of the seeds from a batch of imported marijuana are dead. Intact seeds which are dark brown or grey have the best chance of germinating. Seeds which are whitish, light tan or cracked are probably not viable. Most guide books suggest that growers plant the largest seeds in a batch, but the size of the seed is genetically as well as environmentally determined and does not necessarily relate to its germination potential. If the seeds are fresh, they can be planted one per container. They may be planted in the container in which they are to grow to maturity or in a smaller vessel. Some growers find it more convenient to plant the seeds in small containers to save space during early growth. Seeds with a dubious chance of germination are best started in tissue and then placed in pots as they show signs of life. The wet tissue, napkin or sponge is placed in a container or on a plate, and is covered with plastic wrap. The seeds are check every 12 hours for germination. As soon as the root cracks the skin, the seedling is planted with the emerging point down. Seeds can also be started in tray pots so that large numbers can be tried without using much space. Seedlings and cuttings can be placed in the refrigerator - not the freezer - to slow down their growth if it is inconvenient to plant at the moment. They can be stored in the vegetable crisper of the refrigerator for a week or more, in a moistoned plastic bag. The temperature should be kept above 40 degrees to prevent cell damage. This does not adversely affect the plant's later growth, and, in fact, is an easy way to harden the plants up that are placed outdoors later. [pH:I have wondered if the plants were grown in the refrigerator all the way through picking, and its offspring (from seed) were also grown in such cold temperatures, if future generations of the plant would be able to grow, outside, through winter, by itself.] Seeds should be sown 1/4 - 1/2 inch deep, covered, and then the medium should be patted down. Seeds sown in light soil or planting mixes can be sown one inch deep. Some growers treat the seeds with B1 or the rooting hormone, indolebutyric acid, which is sold as an ingredient in many rooting solutions. Seeds germinated in covered trays or mini-greenhouses grow long, splindly stems unless the top is removed as the first seedlings pop the soil. The medium must be kept moist. One way to make sure that the medium remains moist is to plant the seeds in containers or nursery trays which have been modified to use the wick system. To modify a tray, nylon cord is run horizontally through holes in each of the small growing spaces. The cord should extend downward into a leakproof holder. (Trays come with 2 kinds of holders. Some have drainage holes and some are solid.) The tray is raised from the holder using a couple of pieces of 2x4's running lengthwise which keep tray holders filled with water. The tray will remain moist as long as there is water in the bottom. If the tray is to be moved, it is placed in cardboard box or over a piece of plywood before being filled with water. The light is kept on continuously until the seeds germinate. Most seeds germinate in 3-14 days. Usually fresh seeds germinate faster than old ones. Marijuana Grower's Handbook - part 21 of 33 "Early Growth" Once the seeds germinate, the light is kept on for 18-24 hours a day. Some growers think that there is no significant difference in growth rates between plants growing under 24 hours of light a day (continuous lighting) and those growing under an 18 hour regimen. In controlled experiments there was a significant difference: the plants get off to a faster start given continuous lighting. Some growers cut the light schedule down to conserve electricity. Plants grown under continuous light which are moved outdoors occasionally experience shock. This may be caused by the intense light they receive from the sun combined with the shortened day length. Another popular lighting regimen starts with continuous light. A week after germination the light is cut back one hour so that the regimen consists of 23 hours on and one hour off. The following week the lights are cut back again, to 22 hours of light and 2 of darkness. Each week thereafter, the lights are cut back another hour until the light is on only 12 hours a day. Whenever a light is to be turned on and off periodically, it is best to use a timer to regulate it. The timer is never late, always remembers, and never goes on vacation. [pH:and never goes to jail!] Plants are at their most vulnerable stage immediately after they germinate. They are susceptible to stem rot, which is usually a fungal infection and occurs frequently when the medium is too moist and the roots do not have access to oxygen. On the other hand, if the medium dries out, the plant may be damaged from dehydration. Mice, pet birds, dogs and cats have all been noted to have a fondness for marijuana sprouts and the young plants. [pH:everything must get stoned!] Seedlings given too little light or too warm an environment stretch their stems. The long slender shoot subsequently has problems staying upright - it becomes top-heavy. These plants should be supported using cotton swabs, toothpicks or thin bamboo stakes. Most seedlings survive the pitfalls and within a matter of weeks develop from seedlings into vigorous young plants. During marijuana's early growth, the plant needs little special care. It will have adjusted to its environment and grow at the fastest pace the limiting factors allow. If the plants are in a soilless mix without additives they should be fertilized as soon as they germinate. Plants grown in large containers with soil or a mix with nutrients can usually go for several weeks to a month with no supplements. Within a few weeks the plants grow quite a bit and gardeners thin the plants. If possible, this is not done until the plants indicate sex, so that the grower has a better idea of how many plants to eliminate. The most vigorous, healthy plants are chosen. Marijuana Grower's Handbook - part 22 of 33 "Watering" Growers using passive hydroponic systems only have to water by adding it to the reservoirs, to replenish water lost to evaporation and transpiration. Growers using active hydroponic systems, including drop emitters, adjust the watering cycle so that the medium never loses its moisture. Mediums for active systems are drained well so that the roots come into contact with air. Each medium retains a different volume of water. The plant's size and growth stage, the temperature, and the humidity also affect the amount of water used. Cycles might start at once every six hours of light during the early stages and increase as the plants need it. Plants growing in soil or soiless mixes should be watered before the soil dries out but only after the top layer has lost a bit of its moisture. If the mixture is not soggt and drains well, overwatering is not a problem. Excess moisture drains. Plants have problems with some soils not because they are too wet, but because the soils have too find a texture and do not hold air in pockets between the particles. As long as a medium allows both air and water to penetrate, the roots will remain healthy. If the roots do not have access to air, they grow weak and are attacked by bacteria. Plant leaves catch dust so it is a good idea to spray the plants every 2-4 weeks with a fine spray, letting the water drop off the leaves. Do this before the beginning of the light cycle so the leaves dry off completely, and the glass of the lights is not hot in case water touches it. Some growers spray the leaves weekly with a dilute fertilizer solution. The leaf has pores through which the nutrients can be absorbed and utilized. They claim that the growth rate is increased. In various tests with legal plants, researches have affirmed that plants which are foliar-fed do grow faster. Once the flowers start forming, the plants should not be sprayed because the flowers are susceptible to mold and infections which are promoted by excess humidity.