What causes leaf curl on pepper plants?

Question

I have several varieties of pepper plants and about three fourths of the plants have curling leaves.

Answer 1

As with tomato plants, peppers can also suffer from a virus known as leaf curl. This may be what your pepper plants are experiencing, though it could also be attributed to a lack of water or restricted root growth. The following article should help: https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-leaves-curling.htm