teh purple penguins said:some plants turn purple from cold nights, too much light will make it wither.. not turn purple. some plants have purple, some plants have purple stripes on their stems. all my chile plants have always had purple where the nodes are. purple is god's favorite color love it.
Well, not exactly. Too much light before the plant is ready will cause necrosis on the leaves. One the plant is properly hardened to the light intensity, there shouldn't be any problems. Part of that hardening off can be the production of red or purple pigments in the leaves. I know in the late summer and fall, then my pepper bushes are really loaded down and the sun is very intense, I even get peppers with some purple-ish patches on them that the pods way of protecting itself from the sun. I like to tell people that it's a pepper tan.
Potassium deficiency can also cause a purpling of the leaves, particularly on the bottom of the leaf.