I've included a couple pictures from my garage... The first two are from this year when I tucked away the few trees I have left.
The third picture is a couple years old, so you can see that I used a different configuration (when I had more trees). I, basically, cover the floor with mulch, place my trees and then mulch them up to the first branch. I place a long wooden skewer in each tree to check their water needs. Usually I water them about two or maybe three times all winter! I do have a window in the garage door, but I doubt if they really need any light during their dormancy. That, of course, is my humble opinion.
