Has anyone any experience of warm frames?
I know the theory, in that you build something similar to a cold frame and add a layer of composting material, which gives off a gentle heat suitable for seedlings early in the year, but I was wondering if anyone has ever tried it and has any tips?
While I think of it, any tips about building frames from recycled material? I'd been toying with the idea of gluing/fixing 2l plastic bottles together in various ways. Any other ideas?