How many plants can I grow?

[Seedling]

I have one 400 hs light - I could probably fit 6 3-gallon containers in my grow room. But how many plants can that light support?

[4x5]

You should be fine as long as you have proper reflectors and rotate them around every few days(once they start goin').
By the time you get rid of the males, the remaining plants will have plenty of light.

[LIP]

Exactly, you'll be fine.

When you flower, you'll probs only get 2 females outta the 6, so 200 HPS on each plant will be fine :)