I have two potted Meyers Lemons which I grow in my greenhouse in Colorado. Had these for maybe 15 t0 20 years. They generally have done well producing more lemons than we can use, and are currently in fairly large (20" diam) pots. This year (and a bit of last year) there has been a cycle of blooms, setting fruit, then when the fruitlets are about 1/2" in size they turn yellow then eventually black and fall off. Pretty much all within a couple weeks of each other. This does not seem to be a disease as it does not spread elsewhere on the trees. And older, larger fruits are unaffected. The tree then flowers again and the same cycle repeats. They are on their third flowering from this spring now. I realize that Meyers tend to over set fruit and then loose some to balance their load, but this seems extreme. Basically dropping all the new, small fruits each time. I am wondering what might be the cause(s) here. I think watering and fertilizing are OK. The trees are probably due for a pruning and re-potting, but I have been holding off on that task until this fruit drop problem is resolved. Is there anything people think might be the cause for this?
You might try fertilizing them more. A fertilizer with micro nutrients is best. Something like Miracle Grow works fine. Citrus are heavy feeders and if they have insufficient nutrients they will drop their fruit.
