There are a few vegetables that I grew over the winter. I was successful with growing mustard, endive & radicchio over the winter under a hoop tunnel. If I knew how well they would hold up outside over the winter and how mild our winter would be, I would have grown more! During the winter, I used All Purpose Fabric and 8 mil plastic on my hoop tunnels to protect the plants from frost/snow. Now that it is Spring, I removed the 8 mil plastic. See my posts about coverings for hoop tunnels.
I purchased the seeds for these three plants from Botanical Interests. The mustard is called Ruby Streaks, The endive is Olesh Tres Fine and the radicchio is Palla Rossa Mavrik.