Jay, thanks for the idea. At first I was confused by what you meant by "heat tape" my first thought was the reflective tape used as a heat barrier, but because that didn't make any sense I quickly dropped that idea and thought that some kind of heating cable made more sense. I did some research and found that Heat Tape is a brand (I also discovered that heat tape is simply a term interchangeable with heating cable) but it doesn't appear to be sold in Canada. There are other heating cable brands I can get my hands on but I'm very inexperienced when it comes to using them outside their intended function. Because of this inexperience I'm hesitant to settle on a specific type, I was thinking the Wrap-On brand would work but the instructions say it has to be wrapped up with fiberglass insulation after it's installed. I'm not sure if that's absolutely essential or more or less a way to keep the heat from escaping into the air. I was also looking at the soil heating cables but the reviews aren't promising.
I did have an idea about using a small seed starting mat and placing that inside of a plastic tray/tub lined with heat tape (the kind that's reflective) so it can bounce back the heat and limit heat loss into the air and hook up the mat to a thermostat so I can regulate the heat to something more moderate, at least above -10C. It dipped to -20 last night without windchill, but as you and others have said, staying freezing is better than freeze, thaw, freeze, thaw. I can only try my best and learn from this.
