A root cellar is a great option to include in your food storage plan, since they require no energy to use and require very little maintenance. It’s great if you can build in a root cellar when your home is under construction, but it’s also possible to add a root cellar to your basement, or build one outside your home. Root cellars are a great low-cost, no-energy way to store food and extend the shelf life of fresh produce.
What You Need to Build a Root Cellar
There are four major elements that should be included in every root cellar:
- Ventilation
- Earth-shelter (Either in the basement of your home or buried outside)
- Darkness
- Humidity
For those in warmer areas, check out the post Above Ground Root Cellars. You may not be able to store things like we northerners can, but the Above Ground Root Cellar post will give you some ideas of what you can store, plus tips for year round food production so you always have fresh, local food to enjoy.
Root Cellar Ventilation
This is one of most common mistakes that people make when designing/installing a root cellar. They build their underground food storage airtight to keep things nice and cold, and everything spoils. Why? Some foods give off ethylene gas, which speeds ripening (and rotting). A root cellar that is too airtight may also build up excess humidity, leading to mold and mildew.
How should you ventilate your root cellar? Use two vents, about 3-4 inches in diameter. (Make sure to put screen on the outside to keep mice out!) Place the vents so that one in near the top of the root cellar to exhaust stale air and ethylene gas. The other should be run down to near the floor, to drop in fresh air. 4 inch vents should be adequate for to up to around an 8’x10’ room. If your cellar is larger than this, consider additional venting.
Vegetables and fruits should not be stored together even though temperatures and moisture requirements are similar. As fruits such as apples and pears ripen, they give off ethylene gas which decreases the storage life of vegetables. This is especially evident with potatoes which sprout early if stored near certain fruits.
To combat spoilage from ethylene gas, segregate fruits and veggies that produce excess ethylene gas from those that are easily damaged from ethylene gas. (source)
Fruits and Vegetables that may create excess ethylene gas include:
Apples, apricots, avocados, ripening bananas, blueberries, cantaloupe, citrus fruit (not grapefruit), cranberries, figs, guavas, grapes, green onions, honeydew, ripe kiwi fruit, mangoes, melons, mushrooms, nectarines, okra, papayas, passion fruit, peaches, pears, peppers, persimmons, pineapple, plantains, plums, prunes, quinces, tomatoes and watermelon.
Fruits and vegetables that may be damaged by excess ethylene gas include:
Asparagus, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, chard, cucumbers, cut flowers, eggplant, endive, escarole, florist greens, green beans, kale, kiwi fruit, leafy greens, lettuce, parsley, peas, peppers, potatoes, potted plants, romaine lettuce spinach, squash, sweet potatoes, watercress and yams.
Root Cellar Location – In the Basement or Buried Outside?
By default, the word “cellar” means “underground”. A big part of why root cellars work as well as they do is that the earth remains at a relatively constant (cool) temperature. This temperature will vary, depending on your location. Closer to the equator, and it may be cooler than air temp, but still isn’t likely to act well as a root cellar. At the opposite extreme, you have arctic permafrost, which the native folks use to store whole animals.
For those in cooler areas, the easiest approach is typically to section off a part of the basement (or maybe even the whole basement, if you live in an old farmhouse) for root cellar storage. Old dirt floor basements without heat are great for maintaining proper temperature and humidity levels.
If you are building new, you may want to consider locating your root cellar under your front porch like we did. Our root cellar measures about 8’x8′, which provides plenty of room for our stash of root veggies, plus gives a nice sized porch above. Typically, if you’re building, new your porch floor is formed out of a concrete slab. You need to put a foundation wall under it anyway, so why not put this area to good use? Locating the root cellar outside the footprint of the home permits the root cellar to maintain cooler temperatures more easily than a cellar located within the house.
If you have an existing home you may be able to section off a portion of your basement for a root cellar. Select an area with an existing window if possible, and use the window for ventilation. Fill the window with exterior grade plywood, and cut the necessary vent holes through the plywood. (The plywood also helps block light.) Frame and insulate your desired storage area. Use exterior grade materials that tolerate moisture exposure.
Use an exterior grade door (preferably insulated) on your root cellar to help maintain proper temperature (both in the root cellar and in the house).
Your basement root cellar should have no standard heating or cooling. Take note of ductwork or piping that runs through the ceiling above your root cellar (if any), and make sure vents or hot water pipes are well insulated so they don’t bleed heat into your root cellar.
For an exterior root cellar, similar rules apply – ventilation, earth sheltered and no light. A north facing door is preferred, to avoid sun beating in and heating your cellar up. Aim for at least one to two feet of soil covering the root cellar, and make sure you choose a premade option (some people have used new septic tanks) or materials that are rot resistant and can stand the weight of wet soil.
Root Cellar Lighting
Light exposure is the enemy of food storage. Every time I see people lining up their canning jars or spices on open shelves, I cringe. It looks beautiful, but light bleaches out the color and the nutrient value of foods.
In the root cellar, light exposure may lead to sprouting and green potatoes. If you’re venting through a window, cover the rest of the window. If you have a light in your root cellar so you can see your food storage better, don’t leave the light on when you’re not using it. A hunk of burlap drawn over bins of potatoes or fruit will allow ventilation while still blocking the light. A single incandescent light (switched on exterior) should provide adequate lighting (unless your room is really huge) and, if for some reason your storage gets too cold, you can always use it to introduce a little heat.
Root Cellar Humidity – Keeping Things Moist But Not Wet
Checking the storage chart below, you’ll see that most fruits and vegetables store best with fairly high humidity. If you have a ground or gravel floor in your root cellar, you’re in luck, because the natural ground moisture will help keep your produce damp.
Produce will give off some moisture on its own, but if you note that your produce is shriveling, your root cellar is probably too dry. Take a tip from the grocery stores, and try a little misting action with a spray bottle. Avoid getting any area too wet, as that can lead to standing water and potential mold growth.
How to Store Fruits and Vegetables in the Root Cellar
This is the approach I take in our root cellar…
Onions and garlic don’t mind it a little warmer and drier, so I store them in trays on higher shelves. (They can sit out in your kitchen for a while, too.) Storing in trays on the shelves allows for good ventilation. Also, if an onion starts to go bad, they can be spotted and removed immediately before they spoil the whole batch. My mom used to store her onions in mesh sacks, but many times one bad root would spoil a large number of those around it.
Potatoes go close to the floor where it is cooler and moister (but not wet, because too much moisture will cause rot). I cover the potatoes with burlap or landscape fabricto block out the light (and prevent green potatoes) but allow ventilation.
A few cabbages go on the top shelf, and apples go out in the garage. Pumpkins and squash go on the floor of the canning pantry or the top shelves in the root cellar, because they like it a little warmer and drier.
I store vegetables that need more moisture in buckets, bins or boxes packed with lightly dampened leaves. For us this usually means beets and carrots (I overwinter parsnips out in the garden). I tried packing these vegetables in sawdust and in sand, but prefer the leaves. For me, sand stayed too moist and led to rotting, plus it made a terrible mess. Sawdust was also very messy, but better than sand. It really liked to cling in all the little root hairs. The leaves provide moisture to keep your roots from shriveling up, but are easy to brush off with much less mess. Do use fresh leaves each year to prevent potential pathogen buildup. (Compost the used leaves.)
Recommended Root Cellar Books
The best resource we have found on root cellars is the book Root Cellaring: Natural Cold Storage of Fruits & Vegetables by Mike and Nancy Bubel. No matter what your location or how much space you have, the Bubels are likely to have a root cellar option that will work for you. It contains detailed explanations of how to store vegetables and fruits without electricity with specific temperature and humidity recommendations for each variety. There are also good photos and diagrams, which I really like. The Complete Root Cellar Book is more recently published, and has also gotten good reviews.
Root Cellar Storage Requirements, Temperature and Humidity
The chart below gives preferred temperature and moisture ranges for root cellar storage of a variety of fruits and vegetables. Adapted from the University of Missouri Extension Office.
Click HERE or on image below to download Printable PDF version of Root Cellar Storage Requirements.
Apples
- Cold and moist
- Do not store with vegetables
- 32 to 40 degrees Fahrenheit
- 80 to 90 percent relative humidity
Beans, dry
- Cool and dry
- Home and commercially prepared foods also need a cool, dry storage place
- 32 to 50 degrees Fahrenheit
- 60 to 70 percent relative humidity
Beets
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Brussels sprouts
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Cabbage
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Cabbage, Chinese
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Carrots
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Cauliflower
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Celeriac
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Celery
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Endive (Escarole)
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Garlic
- Cool and dry
- Home and commercially prepared foods also need a cool, dry storage place
- 32 to 35 degrees Fahrenheit ideal
- 60 to 70 percent relative humidity
Grapefruit
- Cold and moist
- Do not store with vegetables
- 32 to 40 degrees Fahrenheit
- 80 to 90 percent relative humidity
Grapes
- Cold and moist
- Do not store with vegetables
- 32 to 40 degrees Fahrenheit
- 80 to 90 percent relative humidity
Horseradish
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
- May be left in the ground undisturbed until needed. Digging can be done unless the soil is frozen hard. A thick layer of mulch may extend your harvest season.
Jerusalem artichoke
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
- May be left in the ground undisturbed until needed. Digging can be done unless the soil is frozen hard. A thick layer of mulch may extend your harvest season.
Kale
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Kohlrabi
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Leeks
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Onions
- Cool and dry
- Home and commercially prepared foods also need a cool, dry storage place
- 32 to 35 degrees Fahrenheit ideal
- 60 to 70 percent relative humidity
Oranges
- Cold and moist
- Do not store with vegetables
- 32 to 40 degrees Fahrenheit
- 80 to 90 percent relative humidity
Parsnips
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Pears
- Cold and moist
- Do not store with vegetables
- 32 to 40 degrees Fahrenheit
- 80 to 90 percent relative humidity
Peas
- Cool and dry
- Home and commercially prepared foods also need a cool, dry storage place
- Airtight container
- 32 to 50 degrees Fahrenheit
- 60 to 70 percent relative humidity
Peppers, hot dried
- Cool and dry
- Home and commercially prepared foods also need a cool, dry storage place
- 32 to 50 degrees Fahrenheit
- 60 to 70 percent relative humidity
Popcorn
- Cool and dry
- Home and commercially prepared foods also need a cool, dry storage place
- Airtight container
- 32 to 50 degrees Fahrenheit
- 60 to 70 percent relative humidity
Potatoes
- Cold and moist
- Do not store with fruits
- 38 to 40 degrees Fahrenheit ideal
- 80 to 90 percent relative humidity
Potatoes, sweet
- Warm and moist
- To keep sweet potatoes from spoiling in warm and moist storage, do not let temperatures drop below 50 degrees Fahrenheit
- 80 to 90 percent relative humidity
Pumpkins
- Warm and dry
- 50 to 55 degrees Fahrenheit
- 60 to 75 percent relative humidity
Radish, winter
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Rutabaga
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
Salsify, oyster plant
- Cold and very moist
- 32 to 40 degrees Fahrenheit
- 90 to 95 percent relative humidity
- May be left in the ground undisturbed until needed. Digging can be done unless the soil is frozen hard. A thick layer of mulch may extend your harvest season.
Squash, winter
- Warm and dry
- 50 to 55 degrees Fahrenheit
- 60 to 75 percent relative humidity
Tomatoes
- Warm and moist
- To keep green tomatoes from spoiling in warm and moist storage, do not let temperatures drop below 50 degrees Fahrenheit
- 80 to 90 percent relative humidity
The length of time that fruits and vegetables keep well in root cellars depends on several factors:
- Early or late crops (late-maturing crops store better)
- Storage conditions (less-than-ideal conditions shorten storage life)
- Fruit and vegetable condition at storage time (proper curing of damage-free produce results in longer storage life).
The odor of strong smelling vegetables, like turnips and cabbage, can be absorbed by fruits and other vegetables. Store them away from other food and where the odor cannot waft into the house.
Do not allow fruits and vegetables to freeze. They will get mushy and rot.
For a detailed explanation of garlic and onion storage see:
You may also want to check out, “The Easiest Vegetable to Store and How to Store Them” and “Top 10 Real Foods to Store Without Electricity“.
Originally published in 2010, updated in 2016.
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