I will be starting my "square foot " garden plants at the end of the week. I put them into a translucent storage bin. I invert the bin, so they rest on the lid, then cover them with the bin, and put a couple of bricks on top, to hold everything down if it gets windy. This is set in the back yard and becomes a DIY mini-greenhouse because the bin is translucent....you can find them cheap at Wally World and I use the largest bin to give the plants "head room". After two weeks the started plants are normally trying to touch the "top" of the container, and it protects them from a freeze or frost. I should be planting by May 1st.
LD