Hi Bill, I was thinking the same thing about it being okay, but not really ideal. I am going to pass on them, because I don't want to build it and then have to build it again with something else. I am sure I can find something else to use, just have to be patient.. Thanks for the input.

The lettuces, spinach, kale and cabbage would be fine out in a coldframe. I've been growing all 4 of those all winter long. The spinach has been doing quite nice. The warm season stuff cucumbers, tomato, squash and melons are okay in the coldframe but not until 2-4 weeks before your last frost date. If you put them out earlier than that they may get too cold at night and become stunted. Unless maybe you want to have a heated coldframe which is them called a hotbed. I use Christmas lights for extra heat. I thought about the buried cable option but I have a way of accidentally digging up things that are buried. As digdirt said coldframes/hotbeds are something that one needs to monitor every day. I use 4 different methods. The frames wide open for days above 40F, cracked open about 3 inched for days 30 to 40, cracked open 1/2 inch for days 25 to 30F and closed fully below 25F. Just harvested a bunch from this frame. :-)

Depends on the crop. If they are cool-season crops, they are hardy to frost if hardened off first. Once they have 2 true leaves, start exposing them to temperatures near freezing (32 to 36 degrees) for a week and then they can go into the cold frame. Most will be hardy to temperatures down to 25 degrees but a few really hardy crops like kale, spinach and mache will tolerate the teens if it warms up at least into the 40s during the day. If it's a warm-season crop, wait until last frost because the frost protection effects are unpredictable. Use a thermometer in your cold frame to get an idea of how much warmth it stores at night.

Hey Kathie, I've never tried the tents you're talking about but would like to give it a try. I usually do sheets or blankets since our weather rarely gets below 28. Even that is rare and doesn't last for more that 12 to 28 hours. I'd love to grown lettuce all season. Thanks for the input. Keep up the good work and stay warm. Brenda Harvey, LA