All winter we have had the electric seed raising bed warming our precious crop of germinating plants. It helps the seeds but keeps the rest of the hot house at a nice temperature as well. Unfortunately the mice like it too. They burrow down into the warm potting mix and make a right old mess. Mel came up with a great way to discourage them though. She puts
cotton wool here and there and every other day applies a few drops of peppermint essential oil. Not only does the hot house smell wonderful but the mice don't seem to like it and haven't been a problem since.