Many vegetables and fruits can be stored in pits, cellars or basements without refrigeration during the cooler months. Successful storage depends upon establishing the right conditions of temperature, humidity and ventilation.
The purpose of all root cellars is their ability to keep food cool, after all, they were the first refrigerators.
A well-insulated root cellar can keep the food inside 40 degrees cooler than the summertime temperatures outside. Winter temperatures can be dependable at above freezing.
Temperatures inside the home, like basements, are noticeably warmer, so food stored inside the house has a tendency to spoil much more rapidly than food stored in a cooler root cellar, primarily due to the presence of a furnace. Keep in mind that temperatures above 45 degrees F cause toughness in most stored vegetables, and encourage undesirable sprouting and considerably more rapid spoilage.
Cured meats, especially ham and bacon, can be stored in the root cellar if the temperature is kept below 40 degrees.
The temperature in a root cellar is never uniform. The temperature near the ceiling is usually 10 degrees warmer than elsewhere in the cellar, so the ceiling area is therefore appropriate for placement of produce that tolerates warmer temperatures well.
Since most fruits and vegetables require high humidity to avoid spoiling, I would strongly suggest putting a hygrometer in your root cellar. Correct humidity is so important to the storage of food that you might even consider separate chambers, one for high humidity and another for low humidity fruits and vegetables. See this chart and this chart for details about humidity requirements.
Dirt floors provide natural moisture and are the floor of choice most of the time, assuming good drainage of the area. High humidity is critical to avoid shriveling of your produce. If humidity is a concern, water can be placed in shallow pans and or you may want to wrap your root vegetables in damp sawdust, sand or moss to reduce surface evaporation.
One of the key control features of a root cellar is the set of air vents that allow air to enter and exit the cellar. Proper circulation is critical in dealing with the ethylene gases released by certain fruits and vegetables.
The ideal set up would be one inlet vent and one outlet vent, although there are a variety of situations in which multiple vents would be appropriate. In general, inlet vents should be placed low, and exit vents placed high. This is conducive to a nice, passive air flow through the root cellar.
The outsides of the vents should all be sealed where they enter the structure with packed cloth, expanding foam or tight rubber gaskets. The vents themselves should be equipped with closing and opening valves, and it is convenient to make these valves operable from outside the root cellar. Closing vents in freezing weather and during summer heat spells will help keep the temperature inside the cellar more uniform. Vent pipes that can be twisted depending on the season to catch cooler or warmer winds are also a good idea. In the spring and the fall, cooling can be encouraged by opening the vents and possibly even the door at night when the temperature outside is dropping below the current temperature in the cellar.
Shelves inside the cellar should be arranged in such a way as to allow circulation between shelves, drawers and the distance between the shelf and wall. Anything placed on the floor should be raised by small blocks or put inside baskets.
At the end of the day, in order to have a successful root cellar, you need to do research about your area and your property in particular. There is also a factor of “trial and error” involved, so you need to understand that your first attempts at a root cellar may or may not be successful. Starting on a smaller scale would be wise.
A root cellar is a major investment of time and space, so taking the time to do your research about your particular area of the country is essential! Contacting your local extension office and asking someone to come out to your place and give you some council as to where to place a root cellar would be the first thing on my list of things to do.
Soils, temperature, drainage and water tables vary from town to town, you really should consult with someone locally.
Root cellar designs tomorrow!