This is my 2nd summer with a meyer lemon in a half wine barrel. It seems to be doing very well overall. It had a bunch of flowers in the spring which set but then the fruits don't grow then they die and fall off. It still has 3 fruits that look like they might make it. I'm guessing that this is maybe normal for such a young plant, but that is my question, is this normal because it is a young plant.

The plant looks really healthy on top but I have noticed a few yellowing leaves on the bottom. I've read they like a lot of nitrogen. Should I stick with a high nitro fertilizer thought out the growing season? I try to stick with the organic fertilizers and have been giving an extract of compost, worm castings, kelp and a high nitro fertilizer like bat or seabird guano once a week, and watering deep twice a week. It's pretty hot here right now. Thanks