Greenhouse: Tomato may be sick, 1 by raggins

raggins wrote:
I transplanted tomato plants from the garden into pots and they have been growing in my greenhouse. I noticed their leaves are turning purple. Does anyone know what is happening? Up to this point they have bloomed and I have a few small tomatos. I was planning on put them back in the garden hopefully next month. I can't decide if I have watered too much or not enough. It has been cloudy for about a week so maybe not enough sun. Help