Root Cellar Troubleshooting

What conditions is a root cellar supposed to provide?

Extension guides describe a cool, dark space with fairly high humidity for many root crops, and good air movement to prevent stale air. Different crops prefer different conditions, so a single space often cannot suit everything at once.

Before troubleshooting, find out what your crops need. Your extension office and published storage charts list the range for each vegetable and fruit, and those targets are what you will measure against.

Keep a simple log of the temperature and humidity once a week through the storage season. A short record helps you see trends, such as slow warming in late winter, and shows whether a change you made actually worked.

• Look up the needs of each crop you store
• Install a thermometer and humidity gauge
• Keep storage dark and airflow steady
• Record readings on a regular schedule

Why is my cellar too warm?

Warm cellars let crops sprout, soften and rot faster. Common causes include a space that is not deep or insulated enough, warm outside air coming in through vents on mild days, heat from a nearby furnace or pipes, and storing the harvest before it has cooled.

Try managing vents so cool night air comes in and warm daytime air stays out. Seal drafts around the door, and consider moving the most sensitive crops to the coolest part of the space.

Remember that different crops want different conditions. Apples and potatoes, for example, should not share a space casually, since some fruits give off gases that affect nearby vegetables. A storage chart from extension covers which crops should be kept apart.

• Open vents at night and close them in warm weather
• Seal gaps around doors and hatches
• Keep heat sources away from the storage area
• Let harvested crops cool before storing

Why is it too dry or too damp?

Crops that shrivel, go soft or wrinkle are often losing moisture to dry air. Crops that grow mold or develop slime may be sitting in air that is too wet, or in a place with poor circulation.

Dry cellars may be helped by damp materials, such as moist sand or by managing ventilation, while damp ones need better airflow and a fix for any water getting in. Seepage and standing water point to a drainage problem outside, which may require help from a builder.

If you cannot control conditions well, store only what the space can handle and use the rest quickly. A smaller, healthier store beats a large one that rots from the bottom up.

• Wrinkled, shriveled crops suggest dry air
• Mold and slime suggest damp or stagnant air
• Fix water entry and drainage first
• Improve airflow before adding moisture control

What causes mold and rot?

Mold grows where moisture, warmth and still air meet. A single rotting vegetable can spread trouble to its neighbors, so check stored produce regularly and remove anything that is soft, moldy or leaking.

Only store sound produce. Bruised, cut or damaged crops rot first. Do not wash root crops before storage unless a source for that crop says so, and handle them gently.

• Inspect stored produce on a regular schedule
• Remove soft or moldy items at once
• Store only undamaged crops
• Give containers space for air to move

How do I handle pests and animals in the cellar?

Mice, rats, insects and other animals take advantage of stored food. Close gaps in walls and around doors, keep vents screened, and avoid leaving open food or debris that attracts them.

If you use traps or other control methods, follow the product label and local rules, and keep them away from children and pets. Pesticides are not a good fit for food storage, so ask your extension office before using any.

• Screen vents and close gaps in walls
• Use containers pests cannot chew through
• Read labels and follow local rules on traps
• Ask extension before using any pesticide

What about safety and food safety?

Enclosed storage spaces can have poor air, so ventilate before you enter, never go in alone if the space seems stale, and be careful with stairs and lighting. Some cellars also collect radon in certain regions, so ask your state health office about testing in your area.

Fresh produce stored in a cellar is a different matter from home-canned food. If you also store canned goods there, follow the storage guidance from the National Center for Home Food Preservation about temperature and conditions.

• Ventilate before entering and light the stairs
• Ask your state health office about radon testing
• Keep canned goods in conditions NCHFP recommends
• Do not store chemicals or fuel near food

Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.