I dug these up about thanksgiving-ish, shook off the excess dirt, then put them in a laundry basket in my 45F garage. I did go out a few times now and poured some water on them, then made sure any excess water as dried out and put them back in the garage. They just look dried up to me and weigh like nothing when I pick them up, and one of them feels like it is rotted. I have never had any luck keeping these over the winter, is there some secret I need to know? It's so much money and bother to have to find them every spring and start over.

I had good luck over many winters in OH by not shaking off the dirt & storing in a trash bag, left open to breathe, in the basement. And a few times, just carrying entire pots to the basement after frost zapped the foliage.

I'm wondering if they got too dry? Are you sure the garage stayed above freezing?

Yes the garage is always above freezing, at 45, it's on it's own heat system because we have paints, tools, batteries and things that can't freeze. I did have them in a large planter on the front porch and I didn't want to haul that all the way to the garage (separate building from the house) since it's so heavy, and also because after I took them out I planted tulips in it for the spring. Maybe they did get too dry, but also one looks rotted and is soft/mushy, so that made me think I got them too wet. Some look too dry and some too wet even though they got the same treatment. So weird. I wonder if I should just plant them in a different pot in the shed? It does stay kind of dark in there, only light is from the little window in the door, except days we are actually out there working, which is not much in the winter months.

That sounds like a good idea to me, give the roots a chance to get growing. It will take a while for foliage to poke up, so light is a moot point until then.

I have several containers of canna, in the fall I either let them freeze back or I cut them early. They go in my basement where it is dark and cool. Water slightly once a month, come spring they are ready to go, done this for several years.