indoor citrus tree has few leaves, losing more now
I had 'few leaves' problem for a long time, but now tree started losing half of its leaves. I was reading the forums here, and trying to give it more time but now I am freaking out and asking your help.
Here are more details;
I have a meyer lemon tree for 3 years.
I am watering it once a week, a quart.
I am using this fertilizer, half a stick once a year : http://www.amazon.com/Miracle-Gro-100396-Citrus-Fertilizer-12-Pack/dp/B000JJYPYE/ref=sr_1_2?ie=UTF8&qid=1379645720&sr=8-2&keywords=citrus+fertilizer
Number of leaves steadily but slowly went down, but recently it accelerated. Now I am losing branches. They are drying out.
I had lemons before and always plenty of flowers.
I am attaching how leaves look. They don't become yellow or dry, but they lose color just before they fall. I don't see any bugs on the leaves.
I think I am losing one of the two major branches.
I would appreciate your help. Please let me know if any more details would be needed.