I have one lemon and one lime tree. They are in 24" pots. Both were repotted with the same soil last spring. I feed them Ferti-Lome 19-10-5 citrus tree food 4 times a year. They go outside in the spring and in the garage for 2 wks in the fall before coming inside. They sit side by side in the house by windows that get sun all day. I water them every 4 days to keep the soil moist but not waterlogged. The lime tree develops an abundant amount of fruit. The problem is the lemon tree develops many flowers, but as the fruit develops many drop off. In the winter months, inside, the tree drops almost half its leaves little by little. While in the garage I treat both trees with an organic insect spray, and inspect them for aphids, etc. before they come inside. When the leaves fall, they look normal, not chewed no yellow spots, etc. Last winter all the leaves on half the tree fell off in about three weeks. Once the trees go outside, the lemon recovers quickly. What can be the problem?
Certified GKH Gardening Expert
This sounds like a watering issue. While you are watering regularly, you may have a dry pocket in the soil (which is why only half the tree loses leaves) that is repelling water. It happens with potting soil if it gets too dry at one time. If you always water the tree from the same spot on the soil, this can cause it too. You should try soaking the tree's container in the tub for 1-2 hours, covered as much as possible with water to try to resoak the soil and change the spot on the soil you water each time so that it is watered evenly across the top over a period of time. It may also be that where you have it placed is getting a draft, either of cold or dry, hot air. Check for this and add a humidifier to the room.