How Big Should A Root Cellar Be [And How Deep]

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A root cellar is used to store a variety of fruits and vegetables. You may be wondering how big and how deep it should be for it to serve you efficiently. We researched the topic, and this is what we discovered.

On average, a root cellar can measure 8 feet long and 5 feet wide to provide adequate storage space of up to 30 bushels. It should be about 10 feet deep since, at this depth, you have a stable temperature of 32 ºF to 40 ºF and humidity levels of 80% to 90%.

There are many factors to consider besides its size and depth before building a root cellar. Continue reading as we will discuss whether a root cellar needs a dirt floor and the ideal temperature to maintain in your cellar. We will also discuss whether root cellars work in a warm climate and whether they need ventilation.

Old stone root cellar with a wooden door, How Big Should A Root Cellar Be [And How Deep]

How to determine the size of a root cellar

The quantity of food you intend to store in your root cellar will determine its size. Typically, a 5-by-8 foot space can hold up to 30 bushels of produce sufficient to last your family through winter.

Although an 8-by-10 foot cellar is rarely filled, an 8-by-8 space can provide adequate storage for vegetables like celery stored in buckets of soil.

The cellar should be 10 feet deep since the temperatures are stable here. Additionally, this depth provides more space to add a layer of gravel which enhances drainage and cleanliness. We will discuss this later.

Adding slatted shelves in your cellar will maximize the available storage space and help you keep things organized.

Does a root cellar need a dirt floor?

An old, abandoned Root Cellar. It was used to store food and produce before refrigeration was invented.

A root cellar needs a dirt floor because the dirt floor retains more natural moisture than concrete or stone, keeping the humidity levels in your cellar high. Elevated humidity levels forestall loss of moisture through evaporation, keeping your vegetables fresh for more extended periods.

Consider the soil type in your cellar since different soil types have various heat capacities and thermal conductivity. Heat capacity is the amount of energy that can be added or removed from the soil before it changes its temperature, whereas thermal conductivity measures how well soil will permit heat transfer.

Looser soils such as sandy and loamy soils are less effective at retaining heat than firmer soils such as clay soil. Additionally, wet soils are less vulnerable to temperature fluctuations in comparison to dry soils. Therefore, the dirt in your root cellar should be dense and kept moist at all times, as this would enable you to maintain stable temperatures in the cellar.

It is advisable to spread gravel on packed earth to keep your feet dry when the ground gets damp. Further, adding several layers of stone on the dirt in your cellar improves drainage, which keeps mold and mildew from building up underneath.

Ideal humidity levels for your root cellar

Your root cellar can maintain an ideal humidity level of 80% to 90% if it has an earthen floor. This humidity level keeps most fruits and vegetables from shriveling. However, you may need to vary the humidity levels in your cellar depending on the type of food stored. Very high humidity levels may cause dried foods or nuts to rot. It may also trigger the germination of some of the stored food.

While most fruits and vegetables prefer high humidity levels of up to 90%, dry food and onions require humidity levels that do not exceed 70%. Additionally, canned goods do not appreciate high humidity levels as this would cause the metal can lids to rust.

It is advisable to partition your root cellar to enable you to maintain suitable storage conditions for different food types.

For foods that require higher humidity, you can increase the moisture in your cellar by gently sprinkling the gravel with water. The large surface area of the gravel enables the water to evaporate quickly, filling the air with moisture.

You can use concrete floors in place of dirt floors, install barrels of rock salt, or increase ventilation in the areas that need lower humidity levels.

You would be better suited to equip your root cellar with a hygrometer as this would enable you to monitor the humidity levels.

This battery-powered hygrometer thermometer enables you to monitor temperature and humidity in real-time. Check it out on Amazon.

What is the best temperature for a root cellar?

Old stone root cellar with a wooden door, Elliston, Newfoundland.

Root cellars should be maintained above freezing temperatures at an ideal level of 32 ºF to 40 ºF. This temperature is suitable for most fruits, vegetables, and dry foods. However, some types of food, such as sweet potatoes, tomatoes, and pumpkins, may require warmer temperatures of about 50 ºF to 60 ºF.

The low temperatures of 32 ºF to 40 ºF slow down the growth of pathogenic fungi that bring about rotting. Moreover, undesirable sprouting is discouraged due to decreased enzyme activity.

Low temperatures also extend the shelf life of fruits by delaying their ripening. At 32 ºF, the biochemical activity that releases ethylene gas decelerates, consequently stalling the ripening of fruits. You can therefore enjoy fresh fruits long after their season has passed.

Ensure that the temperatures in your cellar are consistently above freezing point. Freezing may deteriorate the quality of some food types, such as soft fruits, since the formation of ice crystals may damage cell structure and reduce the longevity of your food once defrosted.

The temperature in your root cellar varies depending on depth, with temperatures near the ceiling being 10 ºF warmer than anywhere else in the cellar. Therefore, you should store foods that tolerate warmer temperatures better, such as onion, near the ceiling.

How to maintain the ideal temperature in a root cellar

Observe the following to maintain favorable temperatures in your root cellar.

  • Dig at least 10 feet deep since, at this level, the temperatures are relatively stable. Also, take into consideration the frost line in your area. You will need to be below the permafrost level to keep your food from freezing.
  • Use rot-resistant wood structures rather than metal because wood is a poor heat conductor.
  • Install shelves at least 2" away from the wall since this allows for better air circulation, which regulates temperatures in your cellar.
  • Install exhaust pipes that will assist in regulating temperatures.
  • Open the door or windows of your cellar at night to allow in the cool air.

It is advisable to have a thermometer in your root cellar as this would enable you to monitor the temperature in your cellar and adjust it as needed.

Do root cellars work in warm climates?

two root cellars in grassy hillside on Fogo Island, Newfoundland

Root cellars work in warm climates since you can still maintain stable temperatures below ground in these areas. However, you may need to dig deeper than colder climates to achieve stable temperatures to protect your produce from the heat.

You would also need to appropriately schedule ventilation in these areas by increasing ventilation during the colder nights and reducing it during the hot days. The right timing would enable you to regulate temperatures in your cellar.

If you live in an area with a warm climate, consider the groundwater levels and frequency of rain before building your root cellar. Since these areas receive torrential seasonal rainfall and the water table is often higher than the colder areas, you should put precautions to ensure that the root cellar does not flood. It would be best if you built your root cellar at a higher altitude to tackle this challenge.

Does a root cellar need ventilation?

Proper ventilation is a crucial control feature for your root cellar. Ventilation regulates temperature by allowing cool air in and ejecting hot air from your cellar. The cool temperatures keep your food from deteriorating.

Ventilation also creates a suitable environment to store different types of food. It eliminates ethylene gases produced by some fruits and vegetables, which may cause other food types to rot. The produce that emits ethylene gases should be stored near the ventilation outlets to keep the gases from building up.

Eliminating the odors produced by an assortment of fruits and vegetables preserves the flavors of your stored food as fresh air circulates in your cellar.

The inlet vents in your cellar should be installed lower than the outlet vents because warm air rises, which creates a conducive environment with free air circulation.

Choose the appropriate time to ventilate your cellar based on the climatic conditions in your region. It is advisable to opt for vents that are equipped with closing and opening valves such that you can choose when to open and close the valves. Moreover, you can install vent pipes that can be twisted to catch cooler or warmer winds, depending on the season.

Final Thoughts

Door is open on rustic, underground root cellar in Elliston on Bonavista Peninsula in Newfoundland, Canada. Destination is Root Cellar Capital of the World.

Root cellars offer an affordable alternative for storing food that can last you through winter. We hope that the information provided in this article will guide you in determining an ideal size and depth for your cellar and maintain suitable conditions to keep your produce fresh for longer.

Please read these articles to find out more about basements:

6 Types Of Basements You Should Know

Can You Finish A Fieldstone Basement?

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