My lemon tree has lost most of it's leaves. It's about 2 - 3 years old. Never has bloomed or ha lemons. It's inside in south window.
Certified GKH Gardening Expert
If this is from seed, then it can take upwards of about 6 years, granted that it comes from a type of lemon that is not open pollinated with wild citrus. In this case, you may never get a viable fruit from the tree. If it is grafted, then you will have to be patient. There are a few things that you will have to do in order for a citrus to remain healthy in container. You will want to add dolomitic lime every few month, along with wettable sulfur. Also give it a citrus fertilizer once per year.
The leaves will naturally fall off indoors, as there is usually not near enough light to keep them growing. There is only enough to keep them alive until the next spring. You can keep it growing by getting a horticultural grade light.
Here is an article that will help: https://www.gardeningknowhow.com/edible/fruits/lemons/growing-lemon-trees-containers.htm