Q.Lemon Tree’s Leaves Fall Off
We move our lemon trees in every year and all the leaves fall off. The tree is full of blooms, and the tree is in such shock. We never get the lemons.

Certified GKH Gardening Expert
Plants need to be acclimated when brought indoors for the winter. This prevents them from going into shock. This article will explain how to do that:
https://www.gardeningknowhow.com/houseplants/hpgen/using-pesticides-and-other-chemicals-on-your-houseplants.htm

Be aware of the humidity level in your house. I used to have the same problem when bringing trees indoors for winter when the heat turned on for the first time and the humidity level dropped sharply.