I don't know how fast your growroom loses heat...so you are going to have to experiment with your setup.
My lights go off at 0830 and come on at 2030 in flower because I have less control over temps than I'd like... but the seedlings and veg are on 24h and I don't worry about m/f ratios, just survival, lol!
Ask again in winter... I may just say to hell with it and move back into the cellar growroom that holds heat better, and tell my tenant to just suck it up and deal!
stinkyattic Reviewed by stinkyattic on . is 15c night temp 2cold for seedlings? hey guys.. well i had heat probs slightly.. now its getting really cold.. my day timew room temp is like 25c.. n just above my 10-11 day old seedlings temps bout 28-29c.. with fans nice and cool.. well lights are on 18/6 from 5am-11pm.. so dark times from11pm till 5am.. i checked the temp at bout 12am lastnight temp was 15c.. and 1 baby has turned slightly purple round the edges of the baby leaves... will my babys be ok at that cold temp 15c for 6hours every night?? if not would closing my Rating: 5