Winter Garden?

I'm thinking about clearing the main garden bed, and preparing it for a second planting. I ordered some yellow onion seed that is suited to my latitude. I could plant it before the frost. I could also plant a cover crop that is good for the soil, but would die in freezing weather. Maybe just some supermarket pinto beans?

This season, I have put up a good supply of frozen broccoli and okra, and the tomato harvest is good. I'll be canning more tomatoes this weekend. My lemons are beginning to turn yellow.