Hey everyone - thanks for your help!

I have been thinking about starting some worms in my square foot garden. I am not quite ready to do an indoor farm, although I am getting there. Anyway, my biggest issue is the winter. It freezes hard here and my garden isn't very deep. I am not sure how well I could insulate it and providing an outside heat source isn't possible. I have read many places that the adults would die off but the babies would hatch in the spring. However, I am feeling terrible about killing off the adult worms. What do you all recommend???