The other idea (besides the 3 ft deep hole) was snugging the coldframe up against and into the compost pile for warmth. (Have access to friends' horse manure :-\if I shovel it) Maybe that would work better. My goal is to find a convenient way to keep the salad crops going through the winter- really growing, not just maintaining, for two of us. My little bubblewrap coldframe won't be big enough if we want some variety and lettuce certainly grows slowly this time of year if at all.
Has anyone tried a coldframe in the compost pile ???