I’m 6 months in with a small Dwarf Improved Meyer Lemon living outside is San Francisco. My yard gets lots of fog but also lots of warm sun; the tree is planted in the sunniest spot. The trouble is that I have a lot of yellow, dropping leaves. I’m fertilizing, watering about 2x a week. I believe I may have a drainage issue or root issue - or is this something else? I don’t see any bugs, mold, eggs etc and it is prolific with fruit… but the fruit stays small and green. Maybe I need to thin the fruit and pull it out of the pot to check drainage? I’d love other opinions before I go through that, thanks!
Welcome to the Forums. You could dig down deep at the far end of the container (where there will be less likelihood of causing root damage) to check the level of moisture in the medium. If it's wet, then there's a good chance the tree has suffered some root damage. Does the container have drainage holes? With the considerable loss of leaves the tree will struggle to generate enough energy to survive let alone further develop the fruit. Therefore I would remove all the flowers and fruit so that all the energy can be put towards recovery.
I wonder if the problem is related to root temperature. Temperatures would be higher and fluctuate more with a metal container. Reference: Container Material Choices - Choosing a Container for Planting - Successful Container Gardens - UniversityofIllinoisExtension growing edible plants in galvanized containers
Soil PH could be high ... you could add some soil acidifier , some magnesium sulphate with sulphur for nice green foilage .
So many possible factors. How big is the tree? Is it root-bound? Is it growing inside or outside? How often are you watering it? I've found that plants do better if grown outside in an environment that closely resembles their native environment as much as possible. Good that it has good drainage since citrus roots don't like to be wet all the time. They also like to dry out for a few days before the next rain/ watering. I'm sure Millet and others can give better diagnosis than me, but I'm guessing you have a wet root problem or some kind of root die back problem. If roots are black instead of white when you pull it out of pot, your roots are dead and would need to repot after removing the dead parts of roots.
