I DO have one potato plant that survived. It is growing in the compost bin! When I dumped the compost today, several leafy arms waved at me. I am sure it is one of the potatoes we found going bad the other day. Usually tossing things in the compost does not encourage them to grow. I guess things were just right for this one potato.
Since potatoes like to be buried -- it promotes the growth of more tubers -- I'll leave this one in place and see how it does. In fact, I'm going to make a point to keep burying it under compost so more tubers will form. One thing for sure, it will have good soil.