This is the best time off the year. Yes better then christmas. This is when all those wonderful buds start to form. The glands swell up with that tasty THC. It all most brings tears of joy to my face when i see those buds.
Flowering occurs when the hours of sunlight start to decrease like around june 21. The days start to get shorter and shorter. If your planting indoors you will have to force your plant to flower. You do this by shorting the light it gets every day. For example you should be giving an indoor plant 18-24 hours of light a day. When you feel your plant is ready to be flowered you simply go out to a pet store and buy a timer that will turn you light on and off. When a plant is flowering it has to be absolute darkness for 12 hours and light for 12 hours. If your like me you want to see those buds forming everyday so you set your light to come on some time your going to be awake to look at it. If you interupt the dark cycle it will throw you plants off by up to a couple weeks.During the dark cycle your plant does not need any Co2. Remeber to turn the Co2 back on when the light comes on. Usally to fully complete you flowering cycle it will take 55-75 days all depending on the strain you are growing. During this cycle your plant is just going to absolutly stink. Be sure to use lots of air freshner because it would be a tragedy if you got busted this late in the cycle.
During this cycle its recomended you use a fertilizer with a high middle number and low outside numbers. If you use fertilizer you should stop three weeks prior to harvest. If you dont you will have a fertilizer taste to your buds when you smoke it. If you stop the fertilizer 3 week before and just use normal water it will flush all the chemicals out and youll have sweet tasting buds. This goes for indoors as well as outdoors.