Root Cellars 101- Root Cellar Design, Use And Mistakes To Avoid

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A root cellar is one of the simplest and most reliable ways to keep food cool without electricity. Long before modern refrigeration, families used natural cooling to store local food through long winters. I don’t know about your area, but we’ve had a lot more power outages in recent years. It makes me appreciate this storage option even more.

When properly designed, a root cellar maintains the right balance of temperature and humidity. This helps to slow microbial growth, reduce food spoilage, and keep produce fresh for months.

Whether you want to build a root cellar from scratch or improve an existing storage area, we can help you out. This guide covers everything from vent pipe placement to the best crops to store to ways to save money on your build.

The images in this article are from our root cellar, which is under our front porch. It’s accessible from the basement, but sits outside the envelop of the home. We use it to store vegetables, home canned goods, wine, and more.

Table of Contents

• What is a Root Cellar?
• 5 “Must Haves” for Building a Root Cellar
  • How much does it cost to build a root cellar?
• 10 Tips for Root Cellar Fruit and Vegetable Storage
  • A Quick Guide: Fruit and Vegetable Storage Chart
• Types of Root Cellars and Natural Cold Storage Options
  • How to Build a Root Cellar in the South
  • Retrofitting a Root Cellar in an Existing Home
  • Add a Root Cellar to a New Home
  • Building a Root Cellar Outside the Home
  • Traditional Root Cellar
  • Earth Berm Root Cellar
  • Barrel in the ground for (Zones 6-9)
  • Barrel in the ground for (Zones 3-6)
• How to Optimize your Root Cellar
  • Root Cellar Temperature
  • Root Cellar Ventilation
  • How to Prevent Ethylene Gas Spoilage
  • Root Cellar Lighting
  • Monitoring Humidity and Temperature
  • Keep Things Moist But Not Wet
  • Ideal Root Cellar Shelving
  • Recommended Root Cellar Books
  • Related Articles

What is a Root Cellar?

A traditional root cellar is an underground storage space for vegetables and fruits. They sometimes include storage for canned goods or other foods. Root cellars take advantage of cool, moist underground conditions to store food without electricity.

5 “Must Haves” for Building a Root Cellar

There are five major elements that a root cellar requires:

1. Ventilation: Some fruits and vegetables give off ethylene gas, which can cause other produce to spoil. Also, a tightly sealed cellar increases mold risk. Make sure fresh air can get in, stale air can get out, and air can circulate around the produce.
2. Earth-shelter: Soil insulates and maintains a cooler temperature. A packed earth floor or gravel floor is better than concrete for keeping moisture (humidity) levels higher. Avoid tree roots.
3. Humidity: A high humidity level of 80-95% keeps produce from drying out. This may cause canning jar lids to rust, so be sure to check lids and rotate stock if you store canned goods in the root cellar. Build in well-drained soil, and avoid flood prone areas.
4. Darkness: Light can trigger sprouting, so if you have a window in your root cellar, keep it covered, and don’t leave the lights on.
5. Shelving/Storage bins: Wood shelving and bins are naturally antibacterial. Wood also conducts heat more slowly than metal, and doesn’t rust. Avoid treated wood, and stick to those that are naturally rot resistant.

How much does it cost to build a root cellar?

The cost of building a root cellar varies widely. If you build a underground sandbag root cellar or remodel a basement corner yourself, it can be as little as $500. Most will cost $2500+.

If you’re looking for the cheapest option, remodeling existing space is usually the least expensive. Doing most or all of your own labor also keeps costs down.

You can reduce the cost by considering the space as both a safe room (storm shelter) and a root cellar. That might get you some funding from FEMA or state programs. See more in our related article: Safe Rooms Checklist. This applies to new home construction and retrofits.

10 Tips for Root Cellar Fruit and Vegetable Storage

Key storage tips to remember:

1. Late-maturing crops store better than early maturing crops. Specific varieties also store better than others, and produce from healthier plants last longer.
2. Check fruit and vegetable condition at storage time. If you note any damage on produce, use those items first. Regularly inspect produce during storage, too.
3. Cure the vegetables that need it before storage. Vegetables that require curing include onions, garlic, winter squash, sweet potatoes, and potatoes.
4. Wipe excess dirt off of root vegetables and store them in lightly dampened leaves or straw. Use fresh leaves each year to prevent potential pathogen buildup. Fresh sand and sawdust will also work, but are messier.
5. It’s okay to wash produce, but make sure dry up excess moisture (and cure if needed) before storage to avoid rot.
6. Less-than-ideal conditions shorten storage life. Try to get as close as possible to target temps and moisture levels. Use different areas of your storage for crops that are a best fit, such as storing carrots lower (colder) and winter squash higher (warmer).
7. Store fruits that give off ethylene gas away from those easily spoiled by ethylene gas. You can also wrap fruit that produces excess ethylene in newspaper to contain the gas.
8. Oher fruits and vegetable may absorb odors from strong smelling vegetables, like turnips and cabbage. Store them away from other food and where the odor cannot waft into the house.
9. Do not allow fruits and vegetables to freeze. They will get mushy and rot.
10. Track temperature and humidity to measure your root cellar performance. Keep the door closed as much as possible to keep the cool moist are inside. Letting heat in or very cold dry air in will reduce the storage life of your fruits and vegetables.

A Quick Guide: Fruit and Vegetable Storage Chart

This chart 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.

See also:

How to Store Potatoes Long Term

Storing Onions so They Last

How to Store Garlic

Types of Root Cellars and Natural Cold Storage Options

Natural cold storage options include (click on any item in the list to jump to more information below):

• Basement or Under Porch Root Cellar – accessible from inside the home
• Traditional Root Cellar – buried below ground, accessible from outside
• Earth Berm – at ground level or partially above ground
• Above Ground Root Cellar – bermed, spring cooled or other above ground root cellars
• Barrel in the ground

You can’t build an underground root cellar if the water table is too high, or soil is too shallow.

How to Build a Root Cellar in the South

Root cellars don’t work as well in warmer climates, because the ground isn’t as cool. In the Above Ground Root Cellar article, my friend Paula shares her southern food production and storage tips. Southern gardeners have the advantage of being able to grow food year round.

The article “Build Your Own Walk In Cooler with a CoolBot Controller and A/C Unit” shares how to build low cost cold storage.

Retrofitting a Root Cellar in an Existing Home

The easiest option for building a root cellar is to section off a part of the basement for your fruit and vegetable storage. Old dirt floor basements without heat are great for maintaining proper temperature and humidity levels. (Make sure to insulate between the house and 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 blocks direct light.

North facing corners work well. They allow you to leave two exterior walls uninsulated, and only insulate the interior walls and ceiling. A north facing wall won’t gain heat from the sun. Use materials that tolerate moisture exposure.

Insulating between the house and root cellar is necessary so you don’t heat the root cellar from above. You also avoid losing house heat into the root cellar.

Your basement root cellar should have no standard heating or cooling. Insulate any ductwork or piping that runs through the ceiling above your root cellar (if any). Make sure vents or hot water pipes are well insulated so they don’t bleed heat into your root cellar.

Add a Root Cellar to a New Home

Many new homes have a small concrete exterior porch. Typically this area has 4ft footings and dirt backfill. You need to put a foundation wall under it anyway, so why not put this area to good use?

To convert this to a root cellar, have the builder put in full footings. Add an insulated exterior grade access door from the basement and two 4 inch vent holes. Add concrete slab on top as normal, and a light inside so you can inspect your storage.

Insulate the walls in contact with the basement, but do not insulate the outside walls exposed to soil. You want to maintain heat transfer between the soil and the root cellar.

Our porch root cellar measures about 6’x8′. It provides plenty of room for our stash of root veggies, plus gives a nice sized porch above. Because the root cellar is outside the footprint of the home, it maintains cooler temperatures more easily.

Building a Root Cellar Outside the Home

For an exterior root cellar, similar rules apply – have good ventilation, keep it earth sheltered and dark. Use a north facing door if possible, to avoid sun beating in and heating your cellar up.

Try for at least one to two feet of soil covering the root cellar. The more soil there is insulating the root cellar, the closer you get to ground temperature.

You may be able to repurpose a new septic tank or large pre-cast culvert. There are some root cellar kits on the market, such as these precast kits.

Whatever you build, use rot resistant materials that can stand the weight of wet soil. Don’t use shipping containers. They are not built to withstand weight on their sides.

Traditional Root Cellar

This is what most of us think of when we hear the phrase “root cellar”. There are insulated doors that lead down into the earth. These cellars go down or into the side of a hill.

Walls are concrete, cinder block, or more creative materials like old tires. You need to make sure the roof and walls are well supported to avoid collapse. Engage an architect or engineer to ensure your safety.

Earth Berm Root Cellar

Above ground root cellars are usually partly sunken with earth mounded on 3 sides and the door avoiding the direct sun. See the Above Ground Root Cellars post for more information.

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Barrel in the ground for (Zones 6-9)

This is a winter storage option. The size and depth depends on the zone you live in. (For more information on zones see: Plant Hardiness Zones & Microclimate.)

Take a large container, with holes drilled in the bottom and top. Bury it level with the soil with a bale of hay as an insulating cover. This will work into zone 7 and possibly into zone 6 depending on cover and conditions.

Barrel in the ground for (Zones 3-6)

Buy one 55gal large heavy duty garbage can, and a 32gal smaller garbage can that fits inside the larger one. Both the larger garbage can and the smaller one need holes in the bottom.

The inside can needs a cover with vents / screen. Cover exterior holes with screens to keep rodents out. It also needs significant insulation above it (over it). Bales of hay, or piles of leaves can insulate it.

Prepare a hole that is deeper than the large garbage can, with rocks and gravel in the bottom to create a simple French drain. Another trick is to dig a very deep, large hole next to the garbage can hole and fill that hole with rocks. The deeper hole acts as a drain for your shallower garbage can root cellar.

Once you have the large garbage can in the ground and secure, lower the smaller one into the larger barrel. Store food in the small barrel.

When you need access, grab from the top or pull out the smaller barrel. This makes it easier to reach food the bottom. There are many variations on this type of in ground storage.

How to Optimize your Root Cellar

To help you get started, we’ll “dig a little deeper” into our root cellar components. These are the keys to successful fruit and vegetable storage.

Root Cellar Temperature

Ideally, we want our root cellar temperature to be similar to refrigerator temperature, around 40 °F (4.4°C). In practice, the temperature varies by location, season, and other factors. Cooler is usually better, as long as it stays above freezing.

The temperature of the soil at 4ft deep is fairly stable. But that temperature varies with latitude and location. Any running underground water will also affect soil temps. The hydrology map will give you an estimated soil temp.

In extreme cold conditions, it’s possible for parts of a root cellar to freeze. The biggest risk is near the vents or exterior door. If you are expecting a short blast of extreme cold, move food storage away from the vents and door. You may even want to plug the vents temporarily.

This shouldn’t be a concern until temperatures drop below zero, or there are high winds driving cold air into the vents.

This soil temp database will likely be more accurate. Your root cellar is likely to be slightly warmer than either estimate, on average. Winter will be cooler than summer, which is what makes them useful for storage crops.

Root Cellar Ventilation

Improper ventilation 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.

We need ventilation because 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. Place the vents so that one is near the top of the root cellar to exhaust stale air and ethylene gas. Run the other vent down to near the floor, to drop in fresh air.

Ideally, these vents are on opposite walls to improve air flow, but ours are next to each other and work reasonably well.

Four inch PVC vent pipes should be adequate for to up to around an 6ft by 8ft room. A larger room like a 8ft by 10ft should have even larger vent pipes or more of them. Make sure to put mesh screen on the outside of the vent pipe to keep mice and other small animals out. Angle or curve vent pipes so rain, snow or debris can’t fall into your root cellar.

How to Prevent Ethylene Gas Spoilage

When fruits such as apples and pears ripen, they give off ethylene gas. Ethylene gas decreases the storage life of some produce. Ethylene gas can cause sprouting, decay, mold, yellowing, shrinking, toughness, softness, bitterness and other damage.

To combat spoilage from ethylene gas, segregate the excess gas producers from crops that get damaged by the gas. Keep your fruits and mushrooms away from your greens and root vegetables. This is a good idea for your refrigerator produce bins, too.

Because our root cellar is fairly small, we usually keep our fruit in the insulated garage or front porch. Storage varieties hold for months in cool conditions.

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 high lumen incandescent or LED light should provide adequate lighting (unless your room is really huge). If for some reason your storage gets too cold, you can use an incandescent light to introduce a little heat.

Monitoring Humidity and Temperature

A high humidity level of 80-95% keeps produce from drying out. The soil provides some humidity.

Keeping track of temperature and humidity is important. You can track humidity with a hygrometer, and temperature with a thermometer like a Digital Hygrometer Indoor Thermometer.

Electronic monitoring is an option if you want more precise records. The Govee Thermometer & Hygrometer has a simple display and can sync via Bluetooth.

Keep Things Moist But Not Wet

Checking the fruit and vegetable storage chart, you’ll see that most store best with fairly high humidity. If you have a dirt or gravel floor in your root cellar, you’re in luck. Natural ground moisture helps to regulate humidity.

If you notice 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 standing water, as that can lead to potential mold growth.

In dry environments, a shallow pan, a tray, or a shallow bucket of water can increase humidity. Be careful with this option, as it can attract pests or result in bacteria or mold growth.

Ideal Root Cellar Shelving

Shelving should allow airflow and add storage area. Keep a gap between the shelving or storage bins and wall to encourage air flow. Keep produce that likes cooler temps lower and food that like warmer temps higher.

Recommended Root Cellar Books

The classic root cellar guide is the book Root Cellaring: Natural Cold Storage of Fruits & Vegetables by Mike and Nancy Bubel.

The book contains detailed explanations of no electricity vegetable and fruits storage 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 also received good reviews. Recipes from the Root Cellar helps you use your storage crops in the kitchen.

Root Cellaring: Natural Cold Storage of Fruits & Vegetables The Complete Root Cellar Book: Building Plans, Uses and 100 Recipes Recipes from the Root Cellar: 270 Fresh Ways to Enjoy Winter Vegetables $9.45 $24.95 $12.99 Buy on Amazon Buy on Amazon Buy on Amazon Root Cellaring: Natural Cold Storage of Fruits & Vegetables $9.45 Buy on Amazon The Complete Root Cellar Book: Building Plans, Uses and 100 Recipes $24.95 Buy on Amazon Recipes from the Root Cellar: 270 Fresh Ways to Enjoy Winter Vegetables $12.99 Buy on Amazon

Related Articles

• Long Shelf Life Foods – What Lasts Best (with Chart)
• Preparedness Storage – Finding Room and Keeping it Safe and Sound
• Home Food Preservation – 11 Ways to Preserve Food at Home

This article is written by Laurie Neverman. Laurie and her family have 35 acres in northeast Wisconsin where they grow a food forest and annual gardens. Along with her passion for growing nutrient dense food, she also enjoys ancient history, adorable ducks, and lifelong learning.

Originally posted in 2010, last updated in 2026.

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