Freeze a few cukes at the end of the season to use later in chilled soups or for a cool summer drink. Peel the cukes, chop them into chunks, drop them into plastic bags and put the bags in the freezer. For a thick off-season slushie, puree the frozen cucumber chunks along with a splash of fruit juice, a few chunks of frozen melon, some honey, and a pinch of pineapple sage.
If your region has mild winters, the best way to keep your carrots is to leave them in the garden under mulch until you’re ready to use them. In colder regions, pull up your carrots before a hard frost sets in and freeze them (sliced or diced) after 2 minutes of blanching. Besides using the carrots as a cooked vegetable, you can use them in muffins and cakes. For these baking uses, first grate the carrots, then give them a quick dip in boiling water. Freeze the grated carrots in recipe-size portions.
You can dry sliced carrots into chips. You can either eat the chips or grind them into flakes. The flakes add sweetness to stews and soups.
Firm, pungent storage onions will keep for months in a cool, dry basement, and even longer in a root cellar. But Vidalias and other sweet, mild onions don’t store well. To preserve their goodness, just chop them up and freeze them in plastic containers.
You can also dry 1⁄2-inch-thick onion slices in a dehydrator, then grind the dried slices into flakes or powder to use as a seasoning.