(this is how the seasons go for Massachusetts, at least...)
Winter is a fine time for making sauerkraut.
Also, curing meats, making sausages and cheeses are fine winter projects.
Gaze longingly at the lush green produce shipped in from California.
You can plant peas! St. Patrick's day is the traditional time for New England. Some 60 days later you'll have a nice early spring crop.
For me, March is also often the season to cook through my grains, in a Jewish-inspired attempt to clean out the pantry of grains before Passover and then start fresh once the matzoh is all used up.
By now asparagus should be in season close enough to New England to not feel quite so guilty about eating it while I wait patiently for our own local produce to be ready to eat.
First farmer's markets of the season! I've never been so excited about lettuce.
My birthday means strawberry season. Now's the time to go pick a whole bunch,
and turn them into jam and strawberry ice cream or freeze laid out on baking sheets (you can bag them once they've frozen hard enough to stay separate.) And of course eat fresh on their own, or in strawberry shortcake.
I'm usually still so excited to be getting fresh green things from the CSA that I don't think about saving any of them for later even though I'm starting to eat leafy greens at every single meal to stay on top of things. This is a fine time to blanch and freeze greens like mizuna, komatsuna and swiss chard. Just squeeze the water out of them after they are cooked or partially cooked in boiling water or in the microwave, then put in a freezer ziploc bag.
Pickling cuke season! Order from a local farm or track them down at the farmers' market and make a bunch now -- they won't be in season in the fall when you might feel more like preserving, but it's not nearly as hot a job as making jam or tomato sauce.
Keep an eye out for peaches. I bought a box of seconds to turn into jam and pie; you could can them in syrup too.
Check your favorite farm or wild blueberry bushes for blueberries.
Abundant lush summer produce is everywhere. If you've got a CSA, you will be swimming in things like eggplants, corn, or tomatoes. Raspberries are in season too!
Corn is best when it's eaten as close to off the vine as you can get it. Unless you've got a cornfield in the backyard though, you may be getting one large batch that's more that you can eat in a day, and then no more for a week. We usually have fresh boiled or grilled corn the day we get it, save some to add to cooked dishes or salsas later in the week, and/or cook a few ears, cut off the kernels, and put them in freezer bags for the winter.
This is usually the tail end of the tomato season - time for a big saucemaking project, especially if you can find them on sale. I never can my sauce, I just make enough that I'll eat it over the winter and freeze it in quart ziplock bags, probably only filling about 1 cup in each bag.
Go foraging for autumn olives and dry them or make fruit leather.
Applesauce! If you don't want to deal with canning, you can always just make sauce, pour into jars or ziplock bags, and freeze them.
Dried apples in a food dehydrator are another good idea.
This may be the best time to find local quinces, which we make quince syrup and quince candy with.
Storage vegetables are one of the easiest things to "put up" for winter! You can store as much squash as you have room for in a cool place in your pantry and it will last for months. Some squashes are a bit more perishable and might like refrigration.
Root vegetables do better in a fairly cold place, e.g. in a garage buried in sand in a barrel.