Re: Garlic and Onions
Your garlic should be fine. The tops may get frozen back but they will grow back. Not sure why you put them in the cold frame. As far as hardiness there is no need extra protection. In fact the cold frame would most likely make the garlic push more growth,freeze back and then lose a some energy that would have eventually went into the bulb.
I generally plant mine outdoors anywhere from mid october to early december and haven’t seen much difference. A straw mulch is helpful to keep it from putting on too much growth in the fall.
Last year the ground was frozen by the time I got around to planting. I just laid the cloves right on top of the soil and covered with straw. By July 1st I had beautiful garlic.