I have a pvc hoop house without much in the way of supplemental heat. temps inside the ghouse have gotten into the 30's pretty often. Although the plants aren't super happy they are still alive. Maybe some other folks can chime in and tell of how low of temps their plants have withstood. They are hardy plants. happy farming.
They should be ok if the temp doesn't drop below freezing. The cold will slow growth, but even seedlings can take it if you don't have sustained temps below freezing. I started seeds in my garage in January with no supplemental heat and temps went to the mid thirties several times. They grew slow as hell, but they are all healthy and growing like weeds now.
Temp controls sex of plant. Too cold=males. Soil 76-80*, air 80-85*=females. My lights out temp is held at 76-80*. I have 2 plants that i keep reveging and they are maintained at these temps and they grow good and are very potent. They 're bubba kush and good as f**k and kill my pain. Plants never need to die unless you want them to. You control thier lives. Keep gowing. Later.
20 ft sticks of 1" pvc are about $4 each, so you do the math on how big of a house you need. then you can get some greenhouse film from farmtek or just get some plastic in the paint department at home depot.... it depends how long you want to keep it for, what you need to hang from it, etc etc....we framed out a small door the help with ease of entrance and to strengthen up the end. I have an intake and exhaust at each end and a few 8 bulb T5's hanging from it and it withstood some crazy winds last night and even an inch of snow a few weeks ago...