Root cellars are old technology that are used to store fruits and vegetables without electricity throughout the winter. Certain crops are considered “good keepers”, and properly stored foods allow fresh food for a family all winter long.
Most of the “good keepers” are root vegetables, thus the name root cellar. However, other foods that can keep all winter include squashes, cabbages, and a few fruit options.
Root cellars are great for keeping produce without electricity. With a root cellar, you don’t have to worry about the power going out, and you can save money, time, and supplies.
A root cellar doesn’t need electricity, canning jars, or a dehydrator. You don’t have to blanch, cut up, or heat any of your food. Just check your root cellar each week and discard foods that are going bad.
A traditional root cellar is dug partially underground. It takes advantage of more stable underground temperatures, and has a vent to the outside to keep it both cold and to remove gases that spoil foods.
Root cellars work by keeping your produce at the right temperature and humidity. This keeps produce from spoiling and drying out.
Obviously, most of us don’t have root cellars in our yard or in our home. However, you probably can find alternative options to meet temperature and humidity requirements to keep “good keepers” longer at your house.
Even if you can’t meet ideal conditions for storage produce, you can probably find places to keep foods much longer than you realize. Storage crops are cheap in the fall, so the longer you can stretch them, the more money you can save!
When storing produce, there are five temperature and humidity conditions that are optimal. Likely you can find or create some of these combinations at your home!
Cold and Very Moist
Cold and very moist means 32-40F and 90-95% relative humidity. This combination is good for your roots (carrots, beets, parsnips, rutabagas, turnips, leeks, winter radishes), as well as your celery, Chinese cabbage, kohlrabi, collards, and short term storage of broccoli and Brussels sprouts.
Roots keep well in the cold and humidity because many are biennials. Those biennial plants grow their root the first year and then sprout and set seed the second. They expect to be cold and underground.
Cold and Moist
Cold and moist remains at 32-40F but at 80-90% relative humidity. Here is where you keep your potatoes, cabbage, apples, grapes, oranges, pears, quince, and grapefruit.
The cold and moist group need to be cold but don’t lose moisture as readily. They aren’t as dependent on humidity as the roots are.
Both of the cold combinations do very well in a root cellar if correct humidity requirements can be met. Humidity is easy to add.
Even if you can’t find places in your house to keep produce below 40F, you can still store a lot of food! The next three combinations are warmer, and easier to meet inside your home.
Cool and Moist
The cool and moist group is a bit warmer, at 40-50F, but still 85-90% relative humidity. Store cucumbers, sweet peppers, cantaloupe, watermelon, eggplant, and ripe tomatoes here.
Cool and moist will help cucumbers, peppers, melons, and tomatoes last as long as possible. These crops will not last all winter, but you might be able to eat your own ripe tomatoes at Christmas.
Since most of these crops will not last very long, you don’t have to find long term storage solutions for them. A dedicated refrigerator set at a higher temperature might work for you.
Cool and Dry
Cool and dry is at 32-50F and 50-70% relative humidity. This is best for garlic and onions. If you have an unheated room or cooler basement, you can meet these requirements.
Warm and Dry
Warm and dry means 50-60F and 60-70% relative humidity. Keep your dried hot peppers, pumpkins, winter squashes, sweet potatoes, and green tomatoes here.
If you have central heating, your house is dry all winter. If you can find a cooler spot in your house, these foods will keep well for you.
Root Cellar Alternatives
Both of the cold combinations can be stored together fairly easily if you can meet the temperature requirements. However, getting temperatures below 40F can be difficult without electricity if you don’t have a way to use outside winter temperatures.
Without a root cellar, you can look into ways to use colder winter temperatures and insulation to maintain them. There may be places inside or outside that you can use.
A few options you might want to try could be:
- Dig a hole outside and install a broken fridge or a cooler
- Dig a hole outside and put in a box for food, then cover it with hay bales
- Put produce in sheds or outbuildings until temperatures are too cold. Insulate the food with blankets, hay, or other materials. Maryland winters can be mild, so this might work really well some years.
- Insulate an area of your basement from the heat. Aim for the north or northeast corner, and try to vent it out a window.
- Some food can remain in the garden, depending on temperature and type of vegetable. You can cover your garden with hay, or bury purchased produce under hay.
- Put boxes on a covered porch, or under a porch, to insulate them from extreme temperatures
Your goal is to figure out a space that can be kept cold and moist. Look around your house and property, and see where you might be able to keep things. Experiment!
For the squashes and potatoes, a great place to provide their warm and drier conditions is the attic. You can vent to an unheated attic to keep it warmer as needed.
Other warm and dry conditions could be in an unheated room. It’s easy to meet squash and potato conditions inside.
Cool and moist produce do not last as long, so meeting their requirements is temporary. You could find a way to store them short term somewhere.
When looking around your house to see what locations might work for storage, start by closing off unheated rooms. Get a thermometer and measure the minimum and maximum temperatures inside the room. From there, you can figure out what would work best in that location.
Best Crops for Root Cellars
Beets – pack beets in damp sawdust, moss, or sand. Keep beets at 32F and 90-95% humidity, putting them in plastic bags if needed. If kept well, beets can last 4-5 months.
Broccoli – even kept in perfect conditions of 32F and 90-95% humidity, broccoli only keeps 2 weeks.
Brussels Sprouts – pick off the stalk and store in perforated plastic bags. If kept at 32F and 90-95% humidity, sprouts can last 3-5 weeks.
Cabbage – can last a long time. Only keep the best cabbages. Store at 32-40F, 90% humidity. Stored cabbages can be stinky, so keep them separate from other vegetables if they are not in a ventilated location. Place cabbages on shelves, a few inches apart, or try layering in hay or wrapping in newspaper individually.
Carrots – can last until May or beyond if kept at 32-40F and 90-95% humidity. Spread an inch thick of damp sawdust in box, put carrots side by side on bedding in single layer, then repeat layers of sawdust and carrots until the box is full. If conditions are too dry, cover with damp newspaper. You can use sand or leaves rather than sawdust.
Cauliflower – will last 2-4 weeks in plastic bags if kept like broccoli.
Collards – do not store long term, but may last 1-3 weeks after all else is gone. Store in perforated plastic bags in 32-40F and 90-95% humidity.
Cucumbers – also do not keep long term. At 45-55F and 80-90% humidity, you may get 2-3 weeks.
Garlic – cure just harvested garlic for a week or two in a sheltered but ventilated place. Snip off roots as close as possible, then trim tops back to 1 inch. In the fridge the bulbs will rot, in the warmth, they will shrivel. Garlic is best stored at 32-40F and 50-60% humidity. You can keep them in paper bags in a cold back room until April.
Kohlrabi – treat like carrots, but it won’t last as long.
Onions – choose late maturing varieties with thin necks, which are often strong tasting raw. Keep onions cool and dry, 32-50F, 60-70% humidity.
Parsnips – may be the hardiest of all roots. Frost makes parsnips sweeter. Layer them in sawdust like carrots.
Peppers – don’t chill peppers, keep them at 45-55F and 80-90% humidity. At 40F they start decaying. Eat red peppers first, they are the most perishable. Put peppers in baskets or in plastic bags if humidity is too low.
Sweet Potatoes – can last until spring if stored right. Wrap them individually in newspaper and store in baskets. Don’t store bruised or cut ones, and eat smaller potatoes first. Store them at 50-60F, and 80-85% humidity. They can store with less humidity if needed.
White Potatoes – best keepers are late potatoes, not summer ones. Cure out of the sun and weather to have them toughen their skins, 1-2 weeks. Keep in cold damp conditions, but never frozen, at 36-40F, 90% humidity. Light and warmth will make them sprout and turn green.
Pumpkins and Winter Squash – pumpkins do better with more humidity, 70-75% rather than 60-70% for squash, because they are more tender. Pumpkins don’t last as long as winter squash. Don’t store squash or pumpkins without a stem, they won’t last. Squash will last to spring, if cured for a hard rind. Acorn squash prefers lower temps and should not be cured. Squash over 55F will go stringy and dry, keep 45-50F.
Winter Radishes – can last until February if stored well. Trim tops, and store like carrots.
Rutabagas – will last 2-4 months if stored like carrots.
Tomatoes – mature green tomatoes will ripen indoors. If harvested from younger plants (rather than those growing all summer), you might get ripe tomatoes on Christmas. Store them without stems so they don’t puncture other fruits. At room temperature, green tomatoes will ripen in 2 weeks. For storage, 55-60F keeps them on hold, at least 28 days before they ripen.
Turnips – treat as carrots.
Most fruits give off ethylene gas. Ethylene gas will cause potatoes to sprout and produce to spoil. They need ventilation to remove the gas.
Apples – early fall apples keep a month or two if you can chill your storage area sufficiently. For all winter storage, get late fall apples once you have cold conditions. Store at 32F and 80-90% humidity.
Grapefruit – can last a month or two at 32-40F and 80-90% humidity.
Oranges and Tangerines – will store a month or two in 32-40F and 80-90% humidity.
Pears – pick them mature but not ripened on tree or else they will be gritty. It is good to wrap pears individually in paper, and store at 32-40F and 80-90% humidity. To ripen them, bring them into 60-65F for a few days.
Getting Below 40F Inside
Reaching lower temperatures outside is much easier than inside. However, if you want to store produce long term inside, there are options.
The easiest way to find below 40F temperatures is through the magic of electricity. You can set a freezer or fridge to above freezing temperatures and add humidity as needed. You’ll have to find a way to ventilate gas out, and will have to pay for electricity.
If your house has a basement, and you have a way to insulate a northern or eastern corner of it, you may be able to benefit from passive cooling instead of electric.
Building an inside root cellar is what I hope to do in my house next year. There are great books and plans online to give you some great ideas.
My basement is unfinished on the northeastern side, and has two windows. With a small insulated room, I’m hoping that the two windows will allow me to bring in cold air at night and vent out ethylene gas. I’ll be able to benefit from a root cellar inside all winter long.
Look around your house and yard. Likely there are several potential locations where you can store food. And remember, even if you can’t maintain ideal temperatures, keeping things cooler will keep them longer.
The longer you can store produce in good condition, the more you can benefit from cheaper fall prices. Your house is unique. Which root cellar options work best for you?