Southern African varieties often flower with as little as 8 or 9 hours of darkness/15 to 16 hours of light. Other 3oth latitude varieties including most indicas flower when the darkness cycle lasts a minimum of 9 to 10 hours. Jamaican and some Southeast Asian varieties will trigger at 11 hours of darkness and ripen during September or October. Equatorial varieties trigger at 12 hours or more of darkness.

Some interesting stuff here:
Marijuana Growers Handbook
Opie Yutts Reviewed by Opie Yutts on . STINKY I NEED HELP WHERE R U? http://boards.cannabis.com/hydroponics/125226-couple-sexing-i-have-bits-pieces.html#post1550073 do u remember this thread when u was telling me to wait and it will show sex soon enough??well it's been 6 and 1/2 weeks and still no show on sex not any of them and i fimmed half of them and left the other half the ones i fimmed are about half the size as the ones not but are alot more bushier so i ask if u would watch this thread as i will get sum pics to put up to show u the ones not fimmed are Rating: 5