If you're using fluorescents, then you can keep the plants pretty close to the lights without worrying about burning them. If they get too tall, you can always train them or top them. They'll grow wider, not taller.

When you decide to flower, you'll want to use a fertilizer that's rich in phosphorus...maybe with a smaller amount of nitrogen mixed in. 6-12-0, or .5-5.0-.5 for example. I wouldn't use something with an outrageous amount of phosphorus, though...like a Miracle Grow product with an NPK like this: "5-36-5". These fertilizers are great for growing huge, bushy roses...but would be overkill for cannabis. You don't want to smoke something that has been heavily saturated with major chemicals for eight weeks.

Bone meal is a good organic choice for flowering, but many might not approve of it due to the highly improbable chance of it containing bovine spongiform encephalopathy, or "Mad Cow Disease." Cases of humans catching this disease are extremely rare, and can only be contracted as a variant of the disease, not MCD itself. Just don't eat spoonfuls of bone meal/blood meal, etc., and you won't have anything to worry about.

Bat guano is a favorite of organic growers. It's usually diluted and the "tea" is used to water the plants 1-3 times per week. Growers have experienced amazing results using this method, and the flavor of the final product is absolutely amazing.

No matter which method of fertilization you plan on using during flowering, try to flush the soil at least once every 1-2 weeks. And really leech it during the last week or two before harvest, or you might end up with buds that have a heavy chemical taste.

Good luck! :rastasmoke: