Answer: If your tree flowers but the flowers and the immature lemons fall off, it either means your tree is just to young to bear fruit, or it means the flowers are not being pollinated by insects. This can happen if the weather is cold (no bee activity), or you've sprayed your yard with insecticides (no bee activity). Next time a flush of flowers opens you can try transferring pollen from one opened flower to another with a small brush such as an artist's camelhair brush. When the flowers are pollinated, they will produce fruit.
Best wishes with your lemon tree!
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