It is possible that your garage will be too warm to keep a consistent freeze on the container; so you will need to keep a careful watch that they continue to have enough water, until you set them out. I also suspect that if you get any growth, the light will not be sufficient for the growing plants needs. You need not worry about garlic bulbils' hardiness any more than about that of open ground planted cloves. Most of them will actually store just fine in a paper lunch bag hung in a corner of your kitchen or in a pantry, and still be ready to plant next spring. Or if you start your onions under lights, garlic bulbils can be grown that way, too.

I would plant them in the pots and sink the pots into the ground. That way you don't have to be concerned with breaking dormancy early, they have plenty of light until dormancy, and they are corralled by the pot so that are easy to move come spring. I plant my bulbils in pots so that I can keep track of them when weeding. The 2 pots on the left are Brown Saxon bulbils. Next are Blanak that look more like grass than garlic. The two pots on the right are second year Iowa German White. In the background is a pineapple and a pepper trying to come back after our brutal summer. I'm still rooting for it.

Agreed about pots in the ground. I have done that quite successfully even here in Minnesota back when I grew and sold perennials. Just make sure your pots are very well drained or the bulbils may end up setting in water and rotting on you. If you force tulips or narcissi, the same process works for garlic, just don't crowd them so tight as for the flower bulbs. Your garlic is not going to be a once and done like forced flower bulbs often are.

I did some normal sized garlic seed in two planters last year. None died. They were large pots, left on the ground with southern exposure. Burke, VA. I think you are better off leaving them in the elements. They need moisture, rain/snow. Anytime I leave something in a shed/garage I forget to water and it dries out.

The bulbils don't need to be babied anymore than the cloves from mature bulbs. There are feral garlics growing all over the country, the plant in general is so widely adapted and mostly completely hardy at least into zone 3, but it is also successfully grown in even harsher climates in many parts of Canada.

I decided to leave them out in the elements and see how that works.