I have had a lemon bonsai for about 18 months now and it has been sick for some time. The tips of new leaves tend to go brown after they reach full size and the leaf later drops off. I lose maybe one leaf every three months.
I water it so the soil is always damp to the touch and fertilize it once a week. I do this for my other two bonsai, a ficus benjamina and a Fukien Tea, and they are both fine.
It is in a well lighted kitchen not far from a large window.
I'm fairly certain this must be a watering/fertilizing issue as none of my trees have any pests I can see.
I am tempted to read forums on care for normal fruit trees but I think watering for full size trees is different so am reluctant to follow advice I find there.
I would be grateful for any help,