Why are the leaves falling off of the tree? We have about 9 lemons starting to grow on the tree.We have the tree inside right now because of the weather.
Some leaf loss can be normal, especially if from the interior of the foliar canopy. This can be due to seasonal shedding of older, interior leaves, change of growing conditions, watering, sunlight exposure.
But if the leaf loss is from the newer leaves on the outer portion of the canopy, or if it is excessive leaf loss (more than 10% to 20% max), then it can be the result of water deficit/drought stress or other physiological stress factors.
If you send photos and better description of the growing conditions and your fertilization and water management program, we may be able to give a better diagnosis and recommendations.