Austrian Winter Pea

Austrian Winter Pea is the cover crop gardeners reach for when they want real nitrogen fixation without waiting around for spring. Sow it in fall and it’ll grow slowly through the cold months, then take off once temperatures rise, building nitrogen in its roots the whole time and putting down a mat of vining growth that shades out winter weeds. Come spring, you chop it, drop it, and plant right into the residue.
It’s also just useful to eat. The shoots and tendrils are tender, sweet, and taste like the best pea you’ve ever had, so even if your main goal is soil building, you can harvest a few handfuls for salads along the way without setting back the crop.
This is a plant that pulls double duty: feeding your soil biology while you’re not actively gardening, and giving you something fresh to eat when not much else is producing. If you’ve got open beds going into the cold season, this is what should be filling them.