Pfg wrote: A solar-powered automatic opener is a godsend when you can't be there to monitor changes in temps and sun. I used one years ago as a weekend gardener in a conventional cold frame.
Now I use a mini-greenhouse stand with shelves. I leave the zipper undone and hang a piece of Reemay over the opening (inside the plastic cover), attached with clothespins top and bottom so it doesn't blow wide open. That has worked well for the last 2 years. I set the plants out on a Friday while I'm there so I can really pay attention to what's going on, and by the time I leave on Monday they are adjusted enough.
I do use a mini-maxi thermometer to keep track of the temps. Here's a record from last year's journal of what was going on when I first put things out. I had to leave that afternoon, but came back the following afternoon and everything was fine.
4/17, Tuesday: 55 last night, 70 at 2 pm.
I woke up in the night and heard the wind howling, so of course I was worried about the plants I left out. But no, today was another gorgeous day. It's supposed to drop down to 34 again tonight, so I setup the Mini GH and managed to get all the tomatoes and snaps inside. Left the door rolled up, put remay over the opening with clothes pins.
After that, night temps went to the low and mid 40's for two weeks, then we had two weeks of below freezing in early May, which killed the buds on many flowering trees. Everything in the stand survived. By then I had put a couple of jugs of water on the bottom shelf to help even out the temps, and it never went below 35 in there. Days were of course warmer, but still quite cold. Btw, I use trays filled with water and capillary matting on raised platforms to prevent drying out while I'm not there. I also sprinkle slug bait generously around the bottom of the stand.