Answer: The leaves of your plants could be affected by a number of things, from insects, to reflected heat, to nutrient deficiency, to watering practices. As long as the plants are producing peppers, I wouldn't be too concerned. The greenhouse plants you purchased were treated to ideal conditions - not standard garden conditions, and may balk when planted outdoors where they have to brave the elements. Just out of curiosity, I'd have my soil tested to see if it's lacking any particular nutrient. Otherwise, just put up with the ugly leaves and enjoy the mature fruits.
Q&A Library Searching Tips