Root cellaring is the simplest form of food preservation. Storing produce in a root cellar can be a good deal if you have the right kind of vegetables and fruits and a humid, cold location. Root cellaring, also called cold storage, cool storage and underground storage, takes advantage of the natural coldness of late fall and winter and the insulating coolness below the ground to keep your harvest fresh for a couple of weeks or an entire winter.
Root cellaring is incredibly easy, but it isn’t foolproof. That is because the low temperatures aren’t powered by electricity, so they’ll vary, as will the shelf life of your produce. As a result, you’ll have to check the food regularly, adjusting the temperature and humidity, and remove any fruits and vegetables that are starting to spoil.
Store only top-quality produce without blemishes, bad spots or wounds. Any weakness can invite decay or disease, which can spread to other fruits and vegetables. And only store produce suited for long-term cold storage. Good choices for root cellaring are apples, cabbages, pears, firm cool-season root crops and hard-shelled squash—the crops that seem to last forever if forgotten in the back of the refrigerator.
Handle produce destined for storage with great care during and after harvesting to avoid bruises and damage. Don’t wash the fruits and vegetables, even if they are dirty. Instead, just rub the soil off with a soft cloth or glove or rinse it off gently under running water. Then let the water evaporate before storing. And if you harvest on a warm autumn day, let the food chill in the refrigerator before you put it into storage. Otherwise, it’ll take a long time to cool down and could spoil in the process.
How It Works
We have come to rely on our refrigerators for storing just about anything. It’s difficult to believe that just a few generations ago, your ancestors used their root cellar for a similar purpose. But why should you bother to use a root cellar in our technological age?
For one, your refrigerator probably is crowded with other things, and you simply don’t have enough space to store the fall harvest from a medium- or large-size garden. Secondly, the conditions in a root cellar can be even better than refrigeration for crops such as garlic, onions and potatoes.
A big part of what you can store in a root cellar depends on your storage conditions. You can keep produce in a barrel buried in the garden, in a foam ice chest in an unheated garage, or in boxes or bags in your basement. If you don’t have space or time to make an extra-cold and extra-humid area, you can keep many vegetables in your basement or an unheated room.
If the temperature stays about 50 degrees Fahrenheit, it’s great for pumpkins, sweet potatoes and winter squash and tolerable for eggplant, garlic, onions, potatoes, tomatillos and green tomatoes. You can make a storage area in any convenient place where the temperature is low, ideally, 32 to 40 degrees F, and the humidity is high, 80 percent or more.
Let’s look at these conditions more closely.
Except for a few fruits and some vegetables, you need to keep your food as close to freezing as possible without letting any of it freeze. The proper range, as mentioned, is 32 to 40 degrees. Put your food in storage after temperatures drop outside so you can use those cold temperatures to cool your stored food. In a basement, open a window or vent when you need to lower the temperature, or you can insulate the space to keep warmer indoor air out.
If you’re storing produce in a covered trash can buried outside, you’ll need just enough soil over and around the container to keep it cold but not freezing. Foam chests are their own insulators.
Most vegetables, except onions and winter squash, shrivel rapidly unless stored in a moist atmosphere where the humidity is between 80 and 95 percent. In a storage room, keep the humidity up by keeping the air quite moist or the food moist in rustproof cans, pails or barrels.
To keep the air in the storage room moist, spray water regularly right on the cement or dirt floor. Or sprinkle the floor with water from a watering can. (If you have got a dirt floor, think about building a wooden slat floor over it so that you won’t be walking around in wet dirt. Or lay down a layer of coarse, well-washed gravel 3 inches thick, and keep that moist.)
Be careful not to water so much that puddles collect. These could easily encourage the growth of molds and bacteria.
You’ll have to sprinkle each time the relative humidity of the air falls below 80 percent (a hygrometer will tell), which could be quite often. Large shallow pans filled with clean water and placed throughout the root cellar can also be used to increase humidity.
If you aren’t able to or don’t desire to go through the trouble of keeping the entire root cellar humid, store produce that is particularly likely to shrivel, such as root crops, in closed rust-proof containers layered in damp sand, burlap or sphagnum moss. Containers such as large crocks, metal cans, tight wooden boxes and barrels are all suitable for this purpose.
Good ventilation is essential for preventing the growth of airborne bacteria and molds that thrive in humid environments. It isn’t so important when you’re just storing a small amount of food in a buried barrel as it is when you are storing a large amount in a storage room. To ventilate, let in fresh, cold outside air, which also helps bring your storage room temperature down to 32 to 40 degrees.
Store fruits and vegetables in a dark place. Food will decay faster if exposed to light.
Get together everything you’ll need for root cellaring so you can bring your produce right from the garden into storage without shifting it from container to container. This will save time and minimize handling, keeping the produce in better condition.
Fortunately, root cellaring doesn’t require any expensive or specialized equipment. All you need are the fruits and vegetables you want to store, containers to store them in and packing materials such as newspaper, hay or leaves to cushion and separate the produce in storage.
Make sure the storage container you choose is free of any substances that would affect the quality of the food you store. Contamination from diseased vegetables will spoil your produce, and the odor and scent of gasoline, cedar or any other strong-smelling substance can be absorbed by vegetables. Wash plastic and metal containers before you use them for storage, and make sure they are dry before you pack produce in them.
Here’s an opportunity to put your recycling creativity to work with the following containers.
Originally designed to store and ship apples and other fruits, wooden boxes make ideal storage units for cold storage. Dry leaves, hay, straw, sphagnum moss or crumpled burlap can all be used to stuff them. When stacking wooden boxes for storage, place furring strips between the boxes and the floor and between individual boxes to permit good air circulation.
Probably the most readily available container option, cardboard boxes are perfectly suitable for storing produce in a root cellar if they’re clean.
Homemade Storage Bins
DIY bins are another good option. You can build bins right into storage areas so that there is no chance of water seeping in from the floor. Make the lowest bins 4 inches above the floor to allow air circulation. And make the storage containers removable so you can take them outdoors at the end of the storage season to wash them thoroughly and air them out.
Plastic/metal trash cans, large pails and barrels are all fine as long as they are rustproof. Fill them with packing material and produce in layers, and finish with another 2-inch layer of additional packing at the top. These containers can also be used for pit storage if they’re waterproof.
Styrofoam Ice Chests
Styrofoam chests, with lids removed, make great containers. A crack or two will do no harm.
Mesh Bags/Orange Crates
These are excellent options for storing produce such as onions that require good air circulation.
Sites for Root Cellaring
From a built-in basement storage room to storing in the garden, a variety of root cellaring options exist to store food through the winter. A basement root cellar is lovely to have because it’s so convenient to use, but it can be expensive to build and may just cancel out any savings you had gained from storing your harvest instead of buying from the grocery store during the winter.
The easiest way to keep vegetables in cold storage is to leave them where they are growing during the late fall and early winter. This only works with extra hardy crops such as winter-keeper cultivars of beets, carrots, parsnips, rutabagas and turnips, as well as durable greens such as Brussels sprouts, evergreen scallions and parsley. And it requires well-drained soil that won’t encourage the roots to rot. If you have a cold frame, you can also grow arugula, Swiss chard, winter lettuce and other cool-season greens.
You can make a small but simple and inexpensive storage area by taking advantage of the steps that lead from your basement to the outside basement door. Install an inside door at the bottom of the steps to keep basement heat out. If you want to create an even larger storage area, build inward into the basement, but take care to insulate this extra interior wall space from the rest of the basement. As you go up the steps, temperatures in the stairwell will decrease, and a little experimenting will help you determine the best levels for the different crops you are storing. Check the humidity, and if it’s too dry put some pans of water at the warmest level to increase it.
Styrofoam Ice Chests
A foam ice chest is a perfect cooler for crops such as apples and green tomatoes. If you have an unheated place that doesn’t actually freeze, such as a garage or porch, these coolers can work well for short periods of time. Add the produce you want to store in the chests, a different one in each chest. (Don’t mix different types of produce.) Put the lid in place, and keep it out of the sun, which might heat up the chest. Produce kept this way will probably be good for several weeks.
A fully or partially buried container makes a good place for storing produce. The earth protects from freezing temperatures as well as keeps the food cool and out of the light. But it doesn’t keep out rodents and other animals, so make sure the container is secure.
It’s also important to make some kind of drainage to prevent water from entering the container and spoiling the food.
Areas of the country that have moderate winters without extreme temperature changes are the best for this kind of cold storage. The earth acts as a good insulator, but there is no guarantee that it’ll hold out freezing temperatures that will freeze your food or high temperatures that can cause food to spoil. Two simple ways to store produce underground are in a wooden box or a sunken trash can.
Make a wooden box 6 feet long, 3 feet wide and 2 feet deep. Standard 2-by-4 wooden boards work well. Use a 1-inch hardware cloth to tightly line the inside to keep out rodents. Make a neat wooden lid for the top.
At harvest time in late autumn, select beets, carrots, parsnips, potatoes, turnips and the like for storage. Rinse them free of soil, but be careful not to bruise the skin. (Let excess water evaporate before storing.) Make a pit to put the box in, preferably on sloping ground so excess water will drain away. Put the box inside and lay a layer of clean, sharp builder’s sand (washed sand) on the box bottom. Then place a layer of root vegetables on top of this, resisting the temptation to just dump vegetables into the pit. Cover this first layer of root crops with a layer of sand, then continue layering like this until you fill the box, finishing with a layer of sand.
Try to keep different vegetables separate from one another, and if snow is likely to make them difficult to find, mark their location. For insulation, close the lid and cover it with bales of straw, and then cover this with a plastic sheet to keep out rain and snow. In the summer, when all the food has been taken from the box, clean everything out and let in sunshine and fresh air.
Built-In Basement Storage
Centrally heated homes with concrete floor basements are generally too warm to be used for cold storage because most vegetables and fruits require temperatures between 32 and 40 degrees. However, with a little ingenuity and investment, part of almost any basement can be successfully converted into a convenient root cellar.
Prepare a room that is separated from the rest of the basement, is reasonably insulated and has a window or other means of allowing cold outside air in on occasion to cool the space. You could try a storage room, about 8-by-10 feet, which should be plenty large for a modern gardener’s storage purposes. You can store 60 bushels of produce in this size room.
If possible, locate the storage room in the northeast or northwest corner of your basement, away from the chimney and heating pipes. The northeast corner takes advantage of the two coldest walls of a house. The northwest corner is second best. You have the added advantage when building into a corner of only having to construct two interior walls to enclose your storage space.
Even this setup won’t give you total control over temperature. That depends largely on the outside weather conditions. In early fall and late spring, daytime temperatures may be higher than you want in the storage area. So close the windows to keep the warmth out. Open the windows whenever the storage room temperature is higher than 40 degrees and the outside temperature is lower. Close them when the room temperature drops to 32 degrees. Obviously, a thermometer is a necessity in a root cellar. Train yourself to check the temperatures outside and inside the root cellar frequently.
Cover the windows with opaque material to keep light out of the storage area. Wide wooden shutters fitted to the outside of the window frame will help if you need to open the windows during the daytime. Also, cover the windows with screening to keep out pests.
Keep the storage room clean to prevent problems with bacteria and molds. The walls, floor, and ceiling should be made of easy-to-clean materials, and bins and storage shelves should be removable for cleaning. Take them outside on a dry summer day and dry brush them or scrub them with soapy water. Be certain they’re completely dry before replacing them in the root cellar. Open the windows and the door and let the breeze blow through the entire room.
Root cellaring is the oldest and simplest method of food preservation. It doesn’t require electricity, expensive or specialized equipment, or take up room in your fridge and freezer. The best part is that you can use what you already have—your home, commonly found containers, produce from your garden—and easily preserve many of your harvests for delightful eating throughout the winter.
This article originally appeared in the Sept./Oct. 2023 issue of Hobby Farms magazine.