Cut the bottom out of plastic milk jugs and leave the top open. It is like a mini-greenhouse and as the weather warms, make the top hole bigger or you will fry them.
Is that okay even if the nights are still low 40s?
“Cut the bottom out of plastic milk jugs and leave the top open.”
Yes, works. I did that when I lived in Nebraska in the late 80’s - planted my tomato plants in Mid-March. They weathered several frosts. Had nice ripe tomatoes by the 4th of July.
Last year here in Ohio we lost tomatoes and peppers that we thought we planted late enough. Might try the milk-jug green house again this year.