excellent website. Territorial Seeds is one that focusses exclusively
on the northern gardener (and the one I buy from. They have lettuces
that overwinter in Michigan under minimal cover. Really).

Diane, though, can plant virtually anything, given her minimum temps of
around 32. She might not be able to get some of the longest season
veggies before it gets hot, such as Brussels sprouts, long season
cabbage, and parsnips. But she can get just about everything else. The
trick is to get something on the ground now that will be ready in 30
days, and something that will be ready in 45, and something that will
be ready in 60. Given the poor quality of the soil peas are a must,
though I myself am partial to favas, which are equal in taste to peas
but condition the soil much better, and also are a tremendous green
manure. But favas make such a jungle, you can not really grow anything
underneath.