You can start flowering at anytime. Some people use a 12/12 light cycle from seed but the yields are lower. Yields are impossible to predict.

If your plants haven't reached maturity yet and you switch to a 12/12 cycle, it'll take a couple of weeks before you see pistils/preflowers with most strains. If you wait until you see alternating nodes and preflowers they will start blooming almost immediately after switching the lights.
dillhole Reviewed by dillhole on . my first grow this is my first time growing anything, im looking for any tips or if im forgetting something. i have 5 plants from bagseed that are a week or 2 old, i forgot when i planted them. i had 6 but i snapped 1. im using a 75w grow light i got for 10 bucks its been working fine and it will have to do until i get cash for a better light. im using potting soil with miracle grow, ive heard miracle grow was bad but i dont see what the problem is. here are some pics. Rating: 5