Question
My lemon tree has suddenly had several leaves turn yellow and fall off on one side.  It has been indoors for several months now and been doing well until recently.  It is located near a sunny window, is still holding onto some of the lemons that were on it when it came indoors in October.  It is within 5 feet of a heat register, but I am not sure that is what's making it lose leaves since it has been in the same spot for so long.  I would appreciate any ideas, I'd hate to lose the tree!

Answer
Hello Sally

I'm guessing that you are able to provide a temperature of at least 68 degrees F for your lemon tree, but direct sun through a window may now be so good as it can 'burn' the leaves - that is - dry them out very quickly.  

Moisture is at least as important as warmth.  Citrus fruit requires a humidity level of about 75% and regular watering and feeding about once a month with a feed especially formulated for the purpose.

You could move your plant to a well lit position, but out of direct sunlight and spray it regularly with water that is just warm.  Water regularly also and feed about once a month.

I hope this helps to perk up your lemon tree.

Gill