While any vegetable can be frozen, not all should be frozen. Veggies with high water content aren't suited for freezer storage. Because you can freeze and thaw most other vegetables without sacrificing flavor or texture, you may find it's easiest to remember which veggies can't be stored in the freezer -- it's a much shorter list.
Vegetables to Freeze
Most vegetables can be frozen. Broccoli, carrots, peppers, zucchini -- the list goes on. Leafy greens like kale and spinach freeze nicely, too. Think of the contents of your grocery store's freezer cases. If you've seen a vegetable there, you can bet it will keep nicely in your own freezer.
An avocado is technically a fruit, but because it's primarily used in savory dishes, it's common to group it in with other vegetables for culinary purposes. Like most vegetables, avocados can be frozen. Puree ripe avocados, mix them with lemon or lime juice and freeze them in airtight containers.
Vegetables Not to Freeze
Juicy, watery veggies turn to soggy mush after being frozen. Keep cucumbers, lettuce, cabbage, radishes, sprouts and celery out of your freezer.
Tomatoes can be frozen whole or cubed, but you won't want to eat them raw later on. Either cook tomatoes down to puree before freezing them, or plan to cook them down in sauces or soups later.
Whole potatoes should not be frozen either, as the texture turns grainy and mushy upon thawing. You can freeze mashed potatoes in airtight containers.
Freezing shouldn't decrease the quality and flavor of vegetables, but it won't increase them either. Only freeze veggies that are tender and fresh enough to eat raw. Wash vegetables thoroughly and cut away any blemishes. Cut vegetables into chunks.
Vegetables should be blanched, or briefly cooked in boiling water, before they're frozen. This process kills enzymes that would otherwise cause the veggies to lose flavor.
If you plan to eat peppers raw when they're thawed, don't blanch them. Only blanch the peppers if you plan use them later in cooked dishes.
To blanch, submerge vegetables in a pot of boiling water. Fill a bowl with ice and water. When the veggies are done, use a strainer to scoop them out of the boiling water and into the ice water to stop them from cooking.
Different vegetables require different amounts of blanching time, but most only need about 2 to 3 minutes in the boiling water. The larger the vegetable, the longer time it needs; for instance, a small ear of corn on the cob needs to be blanched for about 7 minutes. After putting the vegetables into the water, wait for it come to a boil again before starting a timer.
Vegetables that have been blanched before freezing won't require as much cooking time as fresh veggies.
Dry cooled vegetables on paper towels. Pack them in food storage bags made for freezing, pushing out any excess air before sealing the bags. Label each bag with the date.
Most frozen vegetables will keep for 12 to 18 months in the freezer without diminishing quality.