I was gonna ask if you are in clay soil. What hurts a plant the most would be cold soil. It will stop a plant dead in its tracks. Hang in there, there are a lot of us having big problems this year. Cheese cloth or a bed sheet would be my 1st choice before digging them up. If climate gets worse, you know what to do. You'll have some nice "clear" rosin. lol
Obviously it's the concept, not the size. You could rig something with PVC and celophane.
here's the gsc
I put a cover over a frame with 6mil clear plastic, at night I also pull a tarp over the frame & plastic, when it's going to get in the 20s I hook up a propane heater, designed for tents and ice houses, no flame it's called a black cat by Coleman, what gets things moving like molasses is lack of intense sunlight, I put a led on a timer so they were getting a full 12hrs of light, sped things up,....now I have the wet soil and dug up 6-8ft plants, put them large tall sided planters (garbage cans) used the same soil they were planted in, tall sides help hold cross bracing to stabilize plants, I then dragged them into heated shop with 1000watt hps, watered well, 6 plants all finished fine, never even had a sagging leaf, did have a thrip issue though, so never put outside plants in your indoor growing area or it's very likely to infect your grow area with something unwanted, outdoors the bugs are being kept in check by predictors but once in a warm room poof.... Learned the hard way over the years... Good luck
All look ok if not suffering from a little nitrogen def, in my experience when they get hurt from frost/cold the leaves all hang down like they are in serious need of watering... Used to grow gorilla style back in the day in NW USA first frost there was typically sept 1, not until it stayed below freezing for several hours and all the heat was gone from the root zone did they succumb.... You should be fine...
