how cold can a marijuana plant handel? can they handel temps in the 60s in the day and 50s in the nights. can they handell it. I wanted to let my plants flower all the way till end of oct or middle of november be for I have to harvest them. I do have a clear tarp over them to keep them wormer and to seep the rain off them. I really hope thgey can handel a little coldness. the news said its gunna be worming up agen in the next few days here.