I bought a Meyer lemon last year from Costco that was loaded with blooms and placed it in a large pot on my deck where it gets a lot of sun. It lost all its flowers that were on it when I bought it and then had a few more flowers. Most of the baby lemons it produced dropped off before they reached pea size but it had three the size of small grapes that managed to survive the winter. (I'm in northern CA - zone 7 and the plant stays outside). This spring it had a number of curled leaves but the new leaves look fine and it flowered profusely. However, it looks like all the flowers are dropping again and it is not forming any fruits, and the grape sized lemons from last year have now turned black. Today I noticed it has a lot of webs on its leaves. I thought they were spiders because I had seen spiders on the plant but now I am wondering if it is diseased and that is why it does not successfully produce fruit. I have been fertilizing it and trying to water it regularly while not keeping it too wet. Any ideas what its problem might be or how I can get it to set fruit?

I also have a valencia orange in a large pot that had been neglected. Since potting it, it has grown a lot and acquired lots of leaves. It never flowers though. I fertilize that too but am thinking it needs more sunlight (right now it is in a more shady spot than the lemon).