I was going to try to explain why plants turn colors in the cold.
After I was a page into it I realize someone else can explain it better, so I found this that explains it a lot better than I could. :thumbsup:

fall colours
trinitybound Reviewed by trinitybound on . advice please i asked this question on my grow log but got no response ill try here.ok my plant is outdoor and all of a sudden the leavs have turnd purple is this do to the cold nights we have been having?. its supposed to get down to minus 1 tonight and then warm up for a couple weeks again. will my plant survive another cold night or should i harvest. look at pics and tell me what you all think.i would like to leave it for another couple weeks if i can get away with it.some ideas would be great thanks. Rating: 5