I had 18 esrog plants in pots that I grew from seed. I live in western Pennsylvania and they were outdoors until it got cold. Now they are indoors. They are a year old and had been doing beautifully until this past August. Since then, I have been having several problems. 1. Dropping leaves. The leaves drop until there is nothing left but a bare stem. That pretty much is the end of the plant. This happened to about 8 of them. 2. Curling leaves. This happened to one but the new leaves are normal. 3. Yellow leaves. This happened to one but the new leaves are green. I found tiny mites (they look like little white specs on the top of the leaf.) Under a magnifier and light I can see they have 6 legs. I sprayed all the plants, top and underside of all leaves and also the dirt with an insecticidal soap. This seems to have resolved the bug problem. I don't know if the plants with the bare stem are dead or if there is hope for them to recover. I had given up on them. But the main issue is - the 6-8 healthy plants that are left - how can I keep them healthy. Simone
Esrog Plants (a Type of Citrus)
Certified GKH Gardening Expert
I, also, grow many citrus in containers. I can tell you from experience that it is VERY difficult if you are outside of their natural zone. It requires a whole lot of maintenance on your part.
Dolomitic lime, and iron sulfate will be something that you will be using regularly. That size container will also be way too small to keep these trees happy.
It will be best to guide you as you get to certain points, as right now, there are too many things to try to correct on these trees to be able to do this in one answer. Repotting into larger containers will solve most of your issues. From there you have to keep the soil conditioned, as these tree need more soil maintenance than anything I have seen.
For now I will give you a link that is for container oranges, but this will apply to many citrus: https://www.gardeningknowhow.com/edible/fruits/oranges/orange-tree-container-care.htm