The weather has been pretty mild so far this winter, but I am thinking a cold frame will help plant seedlings get an early start.
There are lots and lots of plans for cold frames on the internet. They are pretty much a sloped box with a glass or plastic lid. The walls of the box keep out icy winds, and the glass top works like a greenhouse to keep the tender plant starts warm.
I found a free sliding glass door at a window company that was pretty worn out as a sliding door. It is really heavy so my mom helped to move it. The frame is from two 2x12x8 foot pieces and a 2x6x8 foot piece, cut to fit the size of the door. The slope is just the difference between the back 2x12 and the front 2x6. I left the bottom open for drainage.
I'll try some early salad greens, peas, and some nasturtiums. If I replace the glass door with a screen door later, I might just be able to sneak some basil past the wild bunnies!