Curling leaves can be a sign of cold weather (below 45 degrees) or sun burn from too much heat, the leaves would also be discolored. I do not think a lack of nutrients is to blame. If the plants are in full sun I recommend you move them to a spot where they are out of the heat of the afternoon sun. Another problem could be too much water or poor drainage. Feel the soil. It should be dry to the touch even when you poke your finger one inch into the soil. Only when the soil is dry should you add more water. To encourage drainage make sure the pots are raised just a bit from the ground. I slip plastic bottle caps under my pots so the weight of the container does not block water from flowing freely from the drainage hole in the bottom of the pot. Hope your pepper is happy and healthy after these suggestions. Keep growing, Marianne Binetti