When I first started growing citrus in pots, I would put them in my greenhouse in the winter. I started with just a couple trees. Welllll now I have nearly a dozen different citrus trees and the first one are so large they won't fit in my green house. Soooo we over winter them in the garage now. On nice days I open both the garage doors and we have fluorescent lights in the garage. If its freezing they have to rely on the fluorescent lights. We did this last year and they seemed to do good. So back in the garage they went this winter. I would eventually like a greenhouse for just them but its wayyyyyyyy down the list of gardening gets.
Citrus in the garage.
Mandarins, I have almost eat them all. Each day as I leave for work I go over and pick a couple to take to work with me. Good snacks :O)
Grapefruits one is getting ripe
Lemons getting ripe
Kumquats tree is loaded again this year, they are getting ripe as well. This year I am going to do some of them in a crystallized dried candy. I have canned them in the previous years which works well too.
The Kumquat tree is the most reliable of all the citrus I grow. Its has been loaded every year.