Hi
@Neb, I grow my radishes in small 6 qt storage tubs, they don't make good fruit in the smaller starter cups, so I just try to grow 6 plants in a tub.
My greenhouse alarms started going off last night (below freezing in there) but...
I had put the metal-ized bubble wrap over the top of the growing shelves and made a curtain rod ( 1/2 copper pipe) around the outside of them to hold a set of clear shower curtains about 3" away from the shelves, and put the heating mats under the plants on the bottom shelf. The plants on the shelves are still standing this morning.... The temperatures inside the growing shelves stayed above 40F, the outdoor temperatures were reading 6F.
I am planning on closing out my Garden 2022 posts on New Year's eve, and will then move over to the GARDEN 2023 thread.