We've mostly had a warm winter, but there have been a few cold snaps and so I decided to make a mini-greenhouse for Al, my RES. So far, it has been great. I cut some wire fencing and used that to make a frame around his tub (he is in a large sterilite storage tub); it basically looks like a fence around the tub. I bought some greenhouse plastic sheeting at my local garden center and draped it over the wire fencing, wrapping it around and over. I used bricks and planters to weight it down on the ground at the bottom.
Initially, I tried duct taping it to the wall above the tub, but I found that that was problematic and actually not necessary. Instead, on cold days and nights, I just drape the plastic over the top of the turtle tub, and tuck the edge between the tub and the wall. At night, I tuck the side edges in behind the fencing, and set planters in place to keep the corners tucked. On days that are warm, I pull the top off, lay it back over itself in front, so that the top edge rest on the ground next to the bottom edge, and weight it down with planters so it won't blow around in the wind.
The greenhouse keeps warmth in very well. I monitor it with a thermometer. On days that are sunny, even if it's 60 or below outside, the temp inside could get up above 100 if I kept the plastic entirely closed. For this reason, I pull out the upper corners to let hot air escape on sunny cold days.
On cold nights, it's better to keep the plastic closed and tucked. When temps are below 50 outside, the water heat of the water vapor keeps the temps in the high 60s or low 70s inside the plastic tent.
I actually bought enough plastic to cover my box turtle pen too, but because it has been so warm, we've just been bringing my box turtle inside on the cold nights, and occasionally on a cold day.
Anyway, I just wanted to fill you folks in because I know wintering these guys outdoors can be problematic, and this has been working for me. I suspect that if we moved somewhere with cold winters, this system would still work. Let me know if it works for you.
