Thanks so much for the long and detailed reply. Here's a picture of the whole tree, on the windowsill where I keep it.
I'm in Denmark, which has had terrible weather all week so the tree is possibly lacking some sun. I haven't fertilized it at all yet. Is there a home-made remedy that works well (coffee grounds?) or should I get something specific?
I've started watering the leaves in the shower recently, so hopefully can get rid of whatever mites are there. But it's a new apartment and new plant, so I'm puzzled how they even got there.
Getting rid of the lemons does sound painful. Maybe I can keep the yellow one and remove the two green ones? Or the other way around?
