Q: I have a Meyer lemon tree in a pot outdoors for the summer. When we bought it had one lemon. But it has produced flowers twice and when the lemon reaches pea size they fall off.
A: I think you have a lack of pollination. Meyer lemon is self-fruitful and will typically pollinate itself outdoors but there is no harm in helping the process along. When you see an open flower, note that the pollen inside darkens after a day or so. This indicates the pollen is mature and ready to be transferred. Twist a piece of paper towel into a matchstick-size stick and touch it a few times to the thin pollen-bearing anthers and then to the sticky green stigma in the center of the bloom. After a few days the flower will dry up and a tiny lemon will begin developing in its place.