What is most important for storing produce? The two variables that are most important to control when using a root cellar are temperature and humidity.
Temperature: For best results, we want to keep the temperature between 32 and 40 degrees. Allowing the temperature to rise above 40 degrees will cause the produce to deteriorate more quickly.
Humidity: Keeping the humidity level between 85 and 95% will keep produce from shriveling due to moisture loss.
There are number of methods and materials used to make root cellars. For example, a root cellar can be made from straw bales, trash cans, buried barrels, drain tiles, trenches, crawl spaces, new septic tanks, earth pits, outbuildings and basements. Building plans are beyond the scope of this article, however, an internet search can provide plenty of ideas. (Ward Upham)