I made an interesting discovery yesterday, in anticipation of an ice fishing expedition. Last August, I had put the container with some left over nightcrawlers in our spare refrigerator to save for the next trip. They got over looked. Yesterday I discovered them, and checked on their condition. I found I had over 2 dozen very hypothermic, but very healthy worms! They've been in hibernation for 5 months at 36 degrees. Another container I found didn't fare well at all. There were two differences between the two containers of worms. The failed ones were in the little 1/2 pint Styrofoam store container, with one tiny air hole, and packed in whatever media the grower used. The successful ones I had placed in a pint yogurt container, poked many air holes in the lid, and packed them in Miracle Grow Potting Soil. I've raised worms in dedicated worm boxes outdoors many times, but sever cold has always killed them off. Now I'm thinking I've found a way to winter-over a few starters for the next year.