How to Keep Harvested Vegetables in Cold Storage

High Angle View Of Vegetables In Market

Thomas Irmer/EyeEm/Getty Images

The fall harvest often results in more produce than we can eat. The answer is to store your vegetables to enjoy over the winter. While it's possible to immediately freeze or can some of your harvest, cold storage in a root cellar or other cool dark area is another option—especially if your harvest is too large to effectively process immediately. Many vegetables will keep for months in cold storage if you can provide the right conditions. You can then bring the harvested vegetables out of cold storage to cook or process as time allows.

For effective cold storage, choose your vegetables well, keep an eye on them throughout the winter, and don't be shy about bringing them out of storage to enjoy. They won't last forever.

The Basics of Cold Storage

The term "cold storage" does not mean storing vegetables in a refrigerator. Refrigerators are relatively moist environments that are best for storing vegetables that will be used within a few days. Rather, "cold storage" refers to storing large quantities of just-harvested vegetables in cool but not freezing conditions. Cold storage allows for weeks-long or months-long storage until you are ready to cook or process your vegetables.

Cold-storage vegetables are often divided into dry and moist categories, which are stored in different ways.

Dry vegetables (winter squash, pumpkins, onions, garlic) require less effort to store, but they need more space. Since indoor humidity is usually low during the winter, make use of any unused, dark spaces and corners. These vegetables store best if they are kept up off the floor and are not allowed to touch each other. If you must pile things on top of each other, you will need to check them more frequently.

Moist vegetables (potatoes, root crops, cabbages) are best stored in more humid conditions. They should be stored in a container, rather than exposed to dry air. Traditional methods include storing them in peat moss, sand, sawdust, or newspapers, but you can also use plastic bags or cardboard. If you choose to use plastic, make sure there are a few holes for excess moisture to escape. To contain the odor of stored cabbages, you can wrap them in a couple of sheets of newspaper first.

An easy way to store these moist vegetables is to fill a cardboard box with about 4 inches of sawdust or other insulating material. Lay a single layer of vegetables on top of that. Do not let the vegetables overlap and keep them about 4 inches from the sides of the box. Add another 2- to 3-inch layer of insulating material, then another layer of vegetables. Continue layering until the box is almost full. Finish with a 4-inch layer of insulation. If you are worried the temperature will get too cold in your storage area, increase the top, bottom, and side insulation to 6 to 8 inches or slip the first box into a larger box, with additional insulation. Since these boxes can be large, using a light insulating material will make them easier to lift and move around.

5 Tips for Effective Cold Storage

Choose the Right Cold Storage Location

Most homes will have areas that are naturally well-suited for long-term cold storage of harvested vegetable produce.

  • Basements: Cool, dry basements (50–60 degrees Fahrenheit and 60–65 percent relative humidity) will keep most vegetables for at least a couple of months. Make sure the vegetables have good air circulation and ventilation.
  • Attics and entryways: If these spaces are unheated, they can be used for spreading out and storing vegetables that like dry conditions. Even an unheated spare room can be put to use storing a few winter squash on a dresser or tabletops.
  • Root cellars: For ideal cold, moist conditions, (32–40 degrees Fahrenheit and 90–95 percent relative humidity), consider a root cellar. A root cellar can be defined as any space that remains above freezing—from a bucket in the ground, to a crawl space under the porch, to an unheated section of the basement, to a cement enclosure build into the side of a hill. Even in a root cellar, the vegetables will need ventilation and probably some insulation against temperature fluctuations. You also need to ensure that rodents cannot get to them.

Choose the Right Vegetables for Cold Storage

Store only fully mature vegetables. Immature fruits and vegetables will rot quickly. Hold off harvesting as long as possible, especially with root vegetables that can withstand some frost. Many fully mature vegetables with thick skins can be successfully stored for weeks or sometimes even months.

Examine Vegetables Before Storing

Do not store vegetables that have been bruised or nicked or that show the slightest sign of rot. Be careful when handling them. Remove all excess soil, but don't wash the vegetables; just let them dry and brush off the soil. You can wash them well as you take them out of storage and before using them. Scrubbing vegetables can damage the skins and reduce their suitability for long-term storage.

Prepare the Storage Area

Choose a storage area that can be kept dark and one that will not experience freezing temperatures, which can ruin many vegetables. This may depend somewhat on your climate; in some areas, attics routinely see freezing temperatures and are not suitable as cold storage areas. In milder climates, though, attics and even garages can make for suitable cold-storage areas—provided they do not see excessive heat during hot spells.

Make sure to thoroughly clean your storage area before you begin to store your harvest. And make sure it is rodent-proof. If windows are present, temporarily block them off to keep the storage area dark.

Check Your Stored Vegetable Regularly

Check on your stored vegetables every week or two. Storage times are just approximations since vegetables, temperatures, and conditions can vary widely. Vegetables that begin to show signs of softening should be brought out for immediate use, and any produce that shows spots of decay should be discarded before the decay can spread to other nearby vegetables.

Don't Store Vegetables Too Long

Use vegetables taken from cold storage as soon as possible. It is better to routinely prepare vegetables and cook with them, or to preserve them by canning or freezing as time allows, rather than to try keeping them in cold storage indefinitely.

Tips for Specific Vegetables

  • Cabbages: Harvest cabbages when the heads feel firm and full. Remove outside leaves. Cabbages like high humidity and can be stored in perforated plastic bags. Any plastic bag will do if you punch some hole in it for excess water to escape.
  • Onions and garlic: Dig onions when the tops fall over and allow them to dry in a warm, well-ventilated spot. When the tops are fully dry, cut them down to about 1 inch. Let them continue drying for another one to two weeks. The skins should be papery and flaky. Store in a dry spot that stays just above freezing. The biggest reasons onions do not store well is because they are not fully dried before storage or because they are exposed to warm temperatures and light. Onions with wide necks or green stalks will not store very long. You can braid and hang onions to dry, but as they do, the braids will become brittle and will start breaking. Garlic dries and stores in a similar way. Softneck varieties will keep the longest, usually about six to eight months. Hardnecks should be used within four months
  • Potatoes: Harvest potatoes when their tops begin to die back. Dig and brush off as much soil as possible. Allow them to dry, in a cool, well-ventilated spot. They are ready to store when the skin does not peel off with the pressure of your thumb.
  • Root vegetables (beets, carrots, parsnips, rutabagas, salsify): Dig root vegetables when they have reached the desired size for the particular variety. Most root vegetables are sweeter if you wait until they have been exposed to frost. Once harvested, remove all but 1/2 inch of the tops. This little bit of top growth will seal in juices and seal out problems. You can also remove the taproot that extends below the edible root, but it is not necessary. Root vegetables can be prone to shriveling; storing them in slightly damp sphagnum moss or plastic bags with a few holes punched in them will help hold in moisture. You can keep carrots and parsnips in the ground all winter, but you won't be able to harvest them once the ground freezes.
  • Winter squash and pumpkins: Make sure these are fully ripened, with a rind hard enough to resist being dented with your nail. Leave a couple of inches of stem intact and do not use it as a handle, or you could injure the squash. Allow to cure in a warm, dry, well-ventilated spot for about 10 to 14 days, then store in a cool, dark, dry spot where you can spread them out and keep them separate. (Note: acorn squash stores better if not cured beforehand.)
Vegetable When to Harvest Storage Preferences Months of Storage
Beets At 1–3 in. diameter Cold, moist 5
Cabbage When head feels firm Cold, moist 5
Carrots When shoulders are 1 in. diameter Cold, moist 8
Garlic When lower leaves brown Cool, dry 4–8
Onions Once necks are tight and tops fall Cold, dry 4
Parsnips After a hard frost Cold, moist 4
Potatoes When the vines die back Cold, moist 2–4
Pumpkins When the shells harden Cool. Dry 2
Rutabagas At your preferred size Cold, moist 4
Turnips After a light frost Cool, moist 4
Winter Squash When the shells harden Cool, dry 2–6