By Diane Wright Hirsch, MPH

Senior Extension Educator/Food Safety

cold storage procedure at home for fruits and vegetables

Photo Credit: NAL/USDA

A young couple I know if looking to buy their first house. She prefers older homes with character, he wants space for a big garden. They came upon an older home with a dirt basement floor….I immediately thought that it might be a good candidate for a root cellar. In earlier times, when many people grew their own food, lived miles from the nearest grocery store, and did not have the benefit of electricity or refrigeration, they often stored some fruits and vegetables for the winter in root cellars or outdoor cold storage areas or pits.

Today it can be difficult to use the basement for storage as many of us now use our basements as living spaces. We may have furnaces, boilers or woodstoves in our cellars—instead of dirt floors and cold storage shelves. We do everything we can to keep out the dampness. And houses are built to retain heat in order to save energy. And, of course, in general, Connecticut temperatures seem to be warmer longer into late fall and early winter, than they used to be. All of this means that we just have to be a bit more creative if we want to store our late summer/fall crops into mid-winter.

You should recognize that “ideal” storage conditions for many vegetables are not attainable around the average home. Commercial cold storage options often involve a modified or controlled atmosphere, reducing the oxygen and increasing the carbon dioxide level, while high humidity is maintained in an air−tight, refrigerated storage room. It is important to understand that these conditions cannot be achieved at home…your home-stored apples will not be equal to the quality of a store-bought apple in January or February.

That said, there are many lower-tech options for storing apples and other foods at home. You just have to remember to follow the rules!

  • Pay attention to and monitor temperature, humidity and air flow;
  • Keep fruits away from vegetables (fruits release ethylene which speeds the ripening process of vegetables);
  • Minimize the effects of strong smelling vegetables such as onions, cabbage or rutabagas.

Outdoor Storage

Some vegetables can be stored outdoors—or even remain in your garden, if well protected. Root crops including carrots, parsnips and turnips can remain in the garden, if rodents are not an issue. A well-drained location is essential as a muddy puddle does not do much for your stored carrots. Once the ground is cold, or begins to freeze, protect the vegetables from frost and fluctuating temperatures with insulating materials such as clean straw, hay, dry leaves, corn stalks, or wood shavings, and some soil.

Mounds or pits are a good way to store cabbage and root crops, such as carrots, beets, celery root, kohlrabi, rutabagas, turnips, and winter radishes. Use a well-drained location, and cover the ground with insulating mulch. Vegetables keep very well in pits and mounds, but once these storage areas are opened all the produce should be removed. After it’s removed, the produce will keep for 1 or 2 weeks at most: use it up quickly or cook and freeze for longer storage. If rodents are a problem, try burying a 20-gallon trash can in the ground. Several small holes should be made in the bottom to allow for drainage (keeping in mind that rodents may be able to get through a dime sized hole).

Indoor Storage

A Connecticut home—especially an older one—offers several options for winter storage of fruits and vegetables. You could use a breezeway, a shed, a Bilco-type basement door area or a garage that is not used for storing your automobile, lawn equipment or chemicals that may affect the flavor of your stored produce. You may be lucky enough to live in a house with an old root cellar or a cellar that does not warm up too much when the furnace gets turned on. Check the room temperature to make sure that the area is cool enough (32˚F–60˚F) and be sure that the temperature does not fluctuate too much. The relative humidity (moisture in the air) of these locations will also affect what type of produce can be stored. Some produce (garlic, onions) store better in dry conditions, while others (apples, root crops) prefer conditions to be more humid.

A pantry, attic, or unheated room is useful for short-term storage of potatoes and onions as long as there is no danger of freezing. Low storage temperatures extend the shelf life of dried foods, such as dried beans, herbs, dried fruits and vegetables. A warm storage area, such as an attic, can be a good environment in the fall for drying herbs, beans, walnuts, or hickory nuts.

A well-ventilated basement with central heating is generally dry and has a temperature range of 50˚F to 60˚F. It may be used for ripening tomatoes and for short-term storage of pumpkins, winter squash, potatoes, sweet potatoes, and onions.

Managing your storage area

Once everything is stored away, you will need to monitor your storage areas, paying attention to temperature (can be made cooler or warmer with ventilating windows that can be opened and shut); humidity (a relative humidity of 90%–95% is very moist and good for storage of potatoes and other root crops. A relative humidity of 60%–75% is dry and good for storage of pumpkins and other squash). Check the storage area at least weekly. Look for evidence of rodents. Check to see that produce is still dry. Remove and discard anything that is rotten or moldy.

Food safety and cold storage

Exploding pressure canners and botulism scares can keep folks away from canning, but cold storage is pretty much risk free. If it doesn’t work, you will see, feel or smell that your food has spoiled—and you will not eat it! Cold storage temperatures also slow the growth of spoilage organisms and enzymatic action (causes over-ripening and rotting). However, there are a few food safety hazards you should pay attention to.

First, be sure to use storage containers that are food-grade. Never use drums, garbage cans or containers that might have held garbage, pesticides or other chemicals. Be sure that the insulating materials used are not contaminated with pesticides or manure. These should be new materials and should be used only once as they will become contaminated with mold and bacteria.

An important risk to consider is that when using cold storage, particularly outdoor storage options, you need to be wary of the presence of rodents or the pesky neighborhood raccoon. Be sure to inspect the inside and outside of the root cellar. Look for gaps (even very small ones) between the ceiling and walls, walls and floors and around any air vents or windows. Search areas around vents, joints between the walls and roof and the area under the cellar. Patch any cracks or gaps around pipes or plug openings with steel wool. Use storage containers that animals cannot chew through, such as metal, plastic or tightly woven mesh with openings smaller than ¼ inch. Secure the top of the containers in the cellar or the lids of buried containers so that they cannot be opened by animals.

When you are ready to use your fruits and vegetables during the winter months, inspect everything you take out. While small amounts of mold can be removed from hard fruits and vegetables such as potatoes, generally, if there is mold, we recommend tossing it out. Mold toxins have been associated with allergic reactions and some are cancer causing agents. Wash everything thoroughly with water and a scrub brush before eating.

Finally, at the end of the season, be sure to clean all containers and the room itself in order to reduce the presence of molds and bacteria.

For more information about managing a cold storage area and a storage chart for specific fruits and vegetables, search for the following article, which was used as a source: Storing Vegetables and Fruits at Home, from Washington State University Extension, or contact the Home and Garden Education Center at ladybug@uconn.edu or 1-877-486-6271.