Potatoes and onions require specific conditions to ensure they last as long as possible. This DIY root cellar storage solution will keep them fresh for longer.

Root cellars certainly are the definition of sustainable. The Groundfridge has a capacity of 3000 liters, which the designers claim is the equivalent of 20 refrigerators, holding half a ton of food.

Like a regular root cellar, it stays at a constant 50˚-54˚F temperature all year long. Subscribe to the Daily newsletter. Fast Company's trending stories delivered to you every day ...

To work properly, a root cellar must stay between 32 and 40 degrees Fahrenheit and at 85 to 95 percent humidity. The cool temps slow the release of ethylene gas, halting decomposition.

The root cellar was built in the 1950s, but hasn't been recently used. Mike McCleary Minnie Geiger used root cellars for most of her life on the family farm in Morton County.