Storing Vegetables for the Winter

Fall is an excellent time to consider storing some of your favorite vegetables for use through the long winter months. Home-grown or locally-grown vegetables can be stored and used for several weeks or months. Many of the vegetables that can be successfully stored should be planted later in the growing season for harvest (or purchase) in late summer or early fall.

Vegetables can be grouped according to the best storage conditions: cold (32-40°F) and very moist (90-95% relative humidity); cold (32-40°F) and moist (80-90% relative humidity); warm (50-55°F) and dry (60-75% relative humidity); and cool (32-50°F) and dry (60-70% relative humidity). In general, cabbage, beets, Brussels sprouts, carrots, cauliflower, Chinese cabbage, kohlrabi, kale, leeks, endive, salsify, rutabagas, parsnips, turnips and radishes should be stored in a cold, very moist environment. Irish potatoes should be stored in a cold, moist environment. Onions, garlic and dry beans should be stored in a cold, dry environment. Sweet potatoes should be stored in a warm, moist environment, and pumpkins and winter squash stored in a warm, dry environment.

If frost has prevented you from harvesting all of your tomatoes, don’t worry. Tomatoes can be picked mature green or before they are fully ripe and will ripen inside. To determine if a tomato is mature green, look at the blossom end (bottom) of the fruit. A mature green fruit will have a white "star-like" color change at the bottom. Not all varieties store equally well; yellow tomatoes tend to store better than red-fruited tomatoes. When storing tomatoes (at any stage of ripeness), it is important to follow some key steps: 1. Any fruit that has been bruised or cracked should not be stored. 2. Place the tomatoes in a newspaper-lined box with newspaper placed between each individual fruit but one-layer deep, with the fruit uncovered on the top. 3. Place the box in a dark, humid (70% or more relative humidity) place at room temperature. Do not refrigerate the fruit. Inspect the fruit once a week and remove ripe fruit or any fruit showing signs of decay. Speed of ripening is controlled by temperature; the higher the temperature, the faster the ripening takes place.

Many vegetables that require cool to cold, moist environments can be successfully stored outdoors through the winter. A common method of outdoor storage is in-field storage. Root vegetables such as carrots, turnips and parsnips can be left in the garden where they grew for part or all of winter. When the ground begins to freeze, these vegetables can be covered with straw, hay or leaf mulch for protection.

Beets, cabbage, Chinese cabbage, cauliflower, kale, leeks, onions and spinach can be stored through fall frosts under mulch. Brussels sprouts can withstand freezing temperatures and can be kept in the garden even into December.

Pumpkins should not be harvested before they reach maturity. Maturity is estimated by the thumbnail test. A mature pumpkin will have a hard rind that resists puncture from the thumbnail. Green pumpkins will not ripen or develop full color in storage.

Some vegetables should not be stored with apples. Apples release a gas called ethylene. Ethylene will make carrots bitter tasting and reduce the storage life of Irish potatoes, pumpkins and other winter squash.

For further information about storage of vegetables, consult the following references:

MacKay, Susan. 1979. Home Storage of Fruits and Vegetables. Northeast Regional Agricultural Engineering Service. Extension Publication NRAES-7. 30 pp.

Jones, J. B. 1999. Tomato plant culture. P. 38-41. CRC Press, Boca Raton, Fl.

Lewis Jett, Assistant Professor & State Vegetable Crops Specialist, UMC (573)884-3287