Mostly it depends on what shape yo've pruned your plants into. In my 4x4 closet I have grown 4 bushy plants that were topped several times or 12 of the same strain un touched. Don,t wait too long to begin flowering....a3 foot plant in a 12 inch tall pot can wind up too close to your light if you're not careful. This happened to me once and I have an 8ft. ceiling...