when is it time to harvest?

I just planted 4 days ago. I know I'm very far away but how long till I cut off alll light and begin to flower? Actually how big should the plant be to do this and how do I tell when its time?

expect your plant to triple in size when you change the lights to 12/12. it really depends on the strains and lights etc... but as for me nirvana ww with 400w hps. im at 6 weeks veg and they range from 12" to 16" gonna start flowering tommorow and i expect them to get about 4' tall so ill be tying them down (lst)

K thanks. But when do I go to the 12/12 lite cycle? And how long after that do I cut off the lights? And do they stay off for the remainder of the time

hey if ur growin from seed it usually takes like round 28 days for ur plants to mature. once its mature u can flip to 12/12.