You may have started your tomato/pepper plants too early, but putting them in a cool greenhouse shouldn't hurt them. It will only slow down the growth until it warms up. Make sure they are getting plenty of light. I see you are in zone 6a. I am in zone 6b. I start my tomato/pepper seeds in my greenhouse around March 21st. Our last frost date (varies) is May 15th. By then, my young plants are ready to move outside, although I usually keep most of my peppers in the greenhouse for the entire season. BTW...and you may have done this, I always plant more seeds than plants I need just in case of a mishap, and I lose some.
