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!

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the other things i will put in existing beds and make quick-hoops and cold frames for.