Q.What is causing leaves of potted sweet lime tree to curl up?
Tree is in second year in a very large pot on my patio. I believe there is enough sun (at least 5 hours) and I hand water (use a moisture indicator to measure soil moisture). Had about five limes when purchased, which matured, but there were only two blossoms this spring. Leaves seem quite healthy and upon inspection show no evidence of insects.
I think what is happening is that your tree is still young. Many trees need several years on them to fruit very much. If it's in a very large pot, it's energy is going into growing roots before it turns to flowers and fruit. Your question mentioned curling leaves, so here's some information on that: https://www.gardeningknowhow.com/edible/fruits/citrus/curling-citrus-leaves.htm
In the text of your question you say the leaves seem healthy, so here's an article on lime trees that you might find useful as your tree matures: https://www.gardeningknowhow.com/edible/fruits/lime/potted-lime-trees.htm
