I'm in Salt Lake City, which has a decently cold winter with snow that is punctuated with occasional thawing and full melt off. Temps in the dead of winter can climb as high as 55 but it freezes every night. It is in zone 7.
What can I plant right now in November? Are there "root" crops such as potatoes or garlic that I can put in the ground and expect them to come up in the spring? What about cover crops that will last the winter? My friend tells me that vetch will grow all winter here. Would you recommend a cover crop, or a heavy mulching with hay/straw and leaves?
You should still be ok to plant garlic. I planted winter wheat, lentils, and clover as a cover crop this year. You could still probably plant these. I also just l planted beets, chard, and brassicas. It may be a little late but we shall see. I am sure you could still plant brassica seedlings if any nurseries around still have any. I am also zone 7 Oklahoma City.
Chinese Snow Peas are often planted 3-4 weeks before first frost. The frost will put them into dormancy, but they will awaken when the spring soil begins to warm. You will end up with a 3-4 week head start on a 60-70 day crop. When they begin to show signs of new life in the spring, plant your next succession crop, and you will be on your way to production until the first frost. (That's why they call them "Snow Peas")
i ordered a bunch of things on monday from bountifulgardens.org ,a lot of what livingwind mentioned. compost crops(wheat,rye,vetch,fava,alfalfa) ,winter hardy greens ,and perennial greens/herbs/vegetables. (like those tree kale/collard cuttings!) it all arrived today,from ca to ny in 2 days, now that is fast.!
that site has a category specifically for things you can plant now in cold climates. and another for compost/cover/green-manure crops. we got almost all our seed there this year and pretty happy with everything, you can see the garden in my signature link.
im preparing new beds now for the compost crops.digging out and filling hugel beds across a 30x30' area (whew! ) the other things i will put in existing beds and make quick-hoops and cold frames for.