The main things a lawn wants are water, fertilizer, and sunshine.
The best time to water the lawn is early in the morning, about 4:30AM. Any time between 3AM and 6AM is okay. After that, winds and heat make the water evaporate too fast, and your city’s water pressure drops too low because more humans try to use water then.
Don’t water in the late afternoon or evening, because that makes the lawn remain wet too long at night: dark wet lawns are a breeding ground for mushrooms, molds, and diseases. (Exception: in the Southwest and other environments that are desert-like with ridiculously low humidity, watering in the evening is okay, since few mushrooms or molds live there.)
How much water? You want the water to penetrate 7 inches into the soil, to encourage the grass’s roots to grow long and be hardy. To accomplish that, water a long time. If you water just briefly, the water will evaporate before getting down that deep.
How often to water To water deeply without wasting water, water just twice a week, but make each watering long. Do not water daily. Do not water several times per day. (Exception: if you’re on a hill and the water runs off the hill and onto the street, interrupt your watering until the ground has a chance to soak up the water, then continue.)
Check yourself Make sure at least one inch of water falls on the grass each week. (That’s half an inch per watering, when you water twice a week. To measure the amount of water, you can use a bucket or empty soup can.)
If you don’t water the grass enough, it eventually turns brown. But even before the grass turns brown, it gives you 2 signs of inadequate water:
Fertilizer is a strong chemical. The lawn needs a little bit of it. If you fertilize too much, the lawn will die.
You should fertilize every 2 months, while the grass is growing. In most parts of the USA, the winter is too cold for grass to grow (the grass just sleeps then), so you should fertilize 4 times: early spring, early summer, late summer, and fall.
When you buy a bag of fertilizer, you see 3 numbers on the bag’s front. Typically, those numbers are 32-3-10, which means the fertilizer is 32% nitrogen, 3% phosphorus, 10% potassium, and 55% “other minerals, coatings, binders, and junk.”
If a bag of fertilizer says 10-10-10 instead, it’s mainly for flowers and shrubs rather than grass.
The bag’s back gives more details. If the fertilizer is high-quality, it also includes other minerals the grass needs, such as iron, calcium, magnesium, and sulfur.
Put on fertilizer when the grass is dry, so the fertilizer hits the ground instead of sticking to wet blades. Then immediately water the lawn (so the fertilizer sinks in before it blows away and before it burns any grass blades it landed on).
Fertilize mainly while the grass is growing fast. Don’t fertilize in the winter.
I believe grass can talk and say things such as:
Grass doesn’t like to be cut, but your neighbors will insist that you cut it.
When you cut the grass, don’t cut off more than a third of the grass’s blade at a time: if you cut more, the grass gets traumatized, tries to regrow the blade, and uses all its nitrogen for that activity instead of for growing healthy roots and keeping protective storage. Also, cutting off so much blade makes the bottom part of the grass get too much sunlight and turn gray-brown.
If you want to cut more (because the grass has gotten very tall and your neighbors are ready to kill you), do it in two stages: cut off a little, then cut off a little more a few days later, but never cut more than a third at a time.
Keep the grass as tall as you and your neighbors can bear it. Tall grass has 3 advantages over short grass:
Most experts recommend that you let the grass blades get to about 4 inches tall, then cut back to 3 inches (so you’re cutting off just a quarter of the blade). 3 inches is about the length of your index finger. To get 3 inches, set your lawnmower at one of the “high off the ground” settings. If you wish, instead of letting “4 inches cut to 3,” you can let “3½ inches cut to 2½.”
Here are exceptions:
When grass grows fast (because of rain, fertilizer, and mild temperatures in the 70’s), you must mow often (to avoid lopping off more than a third at a time). When the grass grows slowly, you can wait longer before mowing.
Try to leave the cuttings on the lawn. Though the cuttings look ugly, they actually improve the lawn, since they act as fertilizer and contain many more nutrients than just nitrogen, phosphorus, and potassium. For best results, get a mulching lawnmower (which can chop the cuttings into tiny pieces). If you mow often enough, each mowing will produce cuttings small enough to avoid smothering the grass. Though the cuttings might look big at first, they disappear fast, since most of their bulk is water that evaporates fast.
Mow when the grass is dry, to make the grass easier to cut and the cuttings less bulky.
Killing your enemies
A weed is just a plant that grows too fast and spreads across your lawn too fast.
The best way to avoid weeds is to keep the grass healthy and tall, so weeds don’t get enough sunlight and enough empty space to survive. If you get weeds, the best way to get rid of them is to pull them out by hand, if you have the patience.
Dandelions are hard to pull out, since they have deep roots. If your lawn has a lot of clover, that’s a sign your grass needs more fertilizer.
Some people hate weeds; other people love them. For example, kids love dandelions because their yellow flowers are pretty; but gardeners hate dandelions because they spread too fast and quickly take over your whole lawn; then the wind blows their seeds to the rest of your neighborhood, and your neighbors get angry at you for wrecking their lawns.
If you apply the typical weed killer (called post-emergent weed killer), apply it when the lawn is wet, so the weed killer sticks to the weed’s leaves (which is how it kills the weed). If you apply bug killer, apply it when the lawn is dry, since the bugs spend most of their time in the ground, which is where you want to hit them. One kind of weed killer, called pre-emergent weed killer, attacks the weeds in early spring while they’re still underground, before they emerge from the soil; apply that kind when the lawn is dry.
Weed killers and bug killers also can hurt or kill birds, pets, and small kids, so use the killers as little as possible and just on the parts of the lawn that are having severe problems. Keep kids and pets off those parts of the lawn afterward.
My wife complains that it’s not fair for me to pull out weeds — or put chemicals on them — just because they look different from grass. She calls me a discriminatory racist.
To learn more about lawns, read what agriculture professors say!
Learn from the University of Illinois’ Internet site (Lawn Challenge, www.urbanext.uiuc.edu/lawnchallenge). Then read this delightful book (full of good photos and text) by Professor Nick Christians (from Iowa State U.) and Ashton Ritchie (from The Scotts Company):