More About Winter Vegetable Storage

 

Bucket of freshly harvested Detroit Dark Red beets for storage.
Photo Pam Dawling

 See my previous posts

Here I will tell you more about storage of various crops.

  • Storing crops maximizes their season of availability
  • Many crops can be stored without electricity, perhaps in buildings that serve other uses at the height of the growing season.
  • The Washington State University Extension publication, Storing Vegetables and Fruits at Home, is a good introduction to alternatives to refrigerated storage, using pits, clamps and root cellars. Drawings below are from WSU Storing Vegetables and Fruits at Home
  • There is also good information in old versions of the USDA Agriculture Handbook 66.
  • Some vegetables need to cure before storage in different conditions from those needed for storage. Curing allows skins to harden and some of the starches to convert to sugars.
A storage cabbage, with curled-back leaf on the head, showing maturity.
Photo Bridget Aleshire

Four Sets of Vegetable Storage Conditions

See the chart in my book Sustainable Market Farming, for more details.

By providing storage spaces with just 4 types of conditions, at least 25 crops can be stored.

A= Cold and Moist: 32°F–40°F (0°C–5°C), 80%–95% humidity — refrigerator or winter root cellar conditions. Most roots, greens, leeks. Use ventilated crates, or perforated plastic bags (or mesh net bags for cabbages) indoors. If above 45°F (7°C), roots will start to sprout. Greens benefit from light. See more about root cellars below. Roots can be stored in clamps or pits outdoors – more on those options below.

B= Cool and Fairly Moist: 40°F–50°F (5°C–10°C), 85%–90% humidity — root cellar. Potatoes. Use ventilated crates. Keep in darkness to prevent greening. See the links to my potato storage info.

Trimming garlic stems prior to long-term storage.
Photo by Brittany Lewis

C= Cool and Dry: 32°F–50°F (0°C–10°C), 60%–70% humidity — cooler basements and barns. Garlic and onions. Use net bags or shallow racks. Avoid temperatures of 40°F-56°F (4°C-13°C), or they will sprout. Also avoid reversals of temperature (warm conditions after cold ones). Newer info says 32°F-40°F (0°C-4.5°C). is best for garlic.

Sweet potatoes stored in off-duty wood seed flats.
Credit Nina Gentle

D= Warm and Dry to Fairly Moist: 50°F–60°F (10°C–15°C), 60%–70% humidity — basements. Sweet potatoes and winter squash. Use shallow racks or perforated trays. Sweet potatoes need curing at higher temperatures and humidity before storing.

The entrance to our root cellar.Photo Twin Oaks Community

Root Cellars

  • Potatoes can be stored for five to eight months with a good in-ground root cellar.
  • Potatoes are best stored in a moist, completely dark cellar, at 40°F (5°C) to 50°F (10°C). Ventilate as needed for air exchange and to keep the cellar in the ideal temperature range.
  • Also for apples, cabbage, or root vegetables, but be careful what you mix, because ethylene from the apples, for example, will cause potatoes to sprout!
  • Some people pack unwashed vegetables in boxes of sand, wood ash, sawdust or wood chips. Perforated plastic bags are a modern alternative.
  • Cabbages or pepper plants can be hung upside down in the cellar to ripen, or simply to store.
  • Celery and leeks can be replanted side by side in tubs of soil.
  • See Nancy and Mike Bubel’s book Root Cellaring to learn how to design, build and use a root cellar.
Using a sturdy digging fork to harvest leeks in December.
Photo Pam Dawling

In-Ground Storage

  • Depending on your winter temperatures, some cold-hardy root crops (such as turnips, rutabagas, carrots, parsnips, Jerusalem artichokes and horseradish) and also leeks can be left in place in the ground, with about a foot (30 cm) of insulation (such as straw, dry leaves, chopped corn stalks, or wood shavings) added after the soil temperature drops to “refrigerator temperatures.”
  • Hooped rowcovers or polyethylene low tunnels can keep the worst of the weather off.
  • There could be some losses to rodents, so experiment on a small scale the first winter to see what works for you.
  • Besides being used as a method for storage of hardy crops deep into winter, this can be a useful method of season extension into early winter for less hardy crops such as beets, celery and cabbage, which would not survive all-winter storage this way.
  • In colder regions plan to remove the crops before the soil becomes frozen, or else wait for a thaw.

Drawing credit WSU Storing Vegetables and Fruits at Home

Harvested turnips ready for storage.
Photo Pam Dawling

Storage Clamps (Mounds)

  • Cabbage, kohlrabi, turnips, rutabagas, carrots, parsnips, horseradish, Jerusalem artichokes, salsify and winter radishes can be stored with no electricity use at all, by making temporary insulated outdoor storage mounds (clamps).
  • Mark out a circular or oval pad of soil, lay down some straw or other insulation, pile the roots up in a rounded cone or ridge shape, and cover them with straw and then with soil, making a drainage ditch round the pile. As a chimney for ventilation, leave a tuft of straw poking out the center. Slap the soil in place to protect the straw and shed rainwater.
  • For the back-yarder, various roots can be mixed, or sections of the clamp can be for different crops. Those growing on a large scale would probably want a separate clamp for each crop. It is possible to open one end of a clamp or pit, remove some vegetables, then reseal it, although it takes some care for it to be successful.
  • There is a balance to be found between the thermal buffering of one large clamp and the reduced risk of rot that numerous smaller clamps provide.

Drawing credit WSU Storing Vegetables and Fruits at Home

 Pits and Trenches

  • Dig a hole in the ground, line it with straw, lay in the vegetables, then cover with more straw and soil.
  • To deter rodents, bury large bins such as metal trash cans, layer the vegetables inside with straw, and cover the lid with a mound of more insulation and soil.
  • Trenches can have sidewalls made with boards to extend the height.
  • You can bury insulated boxes in the ground inside a dirt-floored shed or breezeway. Insulated boxes stored in unheated areas need six to eight inches (15–20 cm) of insulation on the bottom, sides and top.

Drawing credit WSU Storing Vegetables and Fruits at Home

Cherokee Purple tomatoes. Don’t store ripening tomatoes with your potatoes!
Photo Southern Exposure Seed Exchange

Ethylene

  • Ethylene is associated with ripening, sprouting and rotting.
  • Some crops produce ethylene in storage — apples, cantaloupes, ripening tomatoes all produce higher than average amounts.
  • Chilling, wounding and pathogen attack can all cause damaged crops to produce ethylene.
  • Some crops, including most cut greens, are not sensitive to ethylene and can be stored in the same space as ethylene-producing crops.
  • Other crops are very sensitive and will deteriorate in a high-ethylene environment. Potatoes will sprout, ripe fruits will go over the top, carrots lose their sweetness and become bitter.

 

Drawing credit WSU Storing Vegetables and Fruits at Home

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