its fine at 32 as long as it gets warm in the day.at the end of the season where i live it drops into the thirtys and fortys at night then back to 60-80 in the day and its fine.I had a plant turn Dark purple almost like plummish black or something last year.Hardly got anything off it tho cuz i messed with it to much and didnt know what i was doing,i dont think it was the cold that made me get a shitty yeild just turned my shit a cool color.