Many farms in this part of Kentucky didn't get electricity until the mid-1940s. A few farmers still remember the strategies their families used to store food without freezers or refrigerators.

Times have changed. Kentucky now has some of the cheapest electricity in the country, and we use more of it than most other Americans. Almost all of it comes from coal-fired power plants. As a result, Kentucky releases 4% of the country's greenhouse gasses, but accounts for just 1.3% of the population. Lexington, the nearest urban center to Frankfort, has the largest per capita carbon footprint of the nation's 100 biggest cities.

Kentucky State University hosts an annual conference in November for limited resource and minority farmers. During a lunch break a few of the conference participants ventured out into the cold to guide us in the construction of a traditional sweet potato storage pit. We placed cured sweet potatoes in a well-drained pit on a thick bed of straw. Layers of sweet potatoes were separated by layers of straw, creating a giant lasagna underground. The final layer of straw was covered by a thick layer of soil and a tarp to keep the potatoes from freezing (too cold) or sprouting (too wet). As we worked, some of the farmers reminisced about other strategies their families used to store food without refrigeration.

We will use thermocouples attached to a datalogger to continuously monitor temperatures at the soil surface and at all layers of the pit. Over the course of the winter we will remove sweet potatoes periodically to compare their storage life to that of sweet potatoes stored in the cool, dry basement where we kept our seed potatoes through the winter last year. Sweet potatoes store best at temperatures in the mid-50s, so the biggest concern with the pit is that the temperature will get too low.

Sweet potato storage pits have been used for centuries in South and Central America, Polynesia, and Africa. The size, shape, and structure of sweet potato storage pits typically used in the American South is very similar to that of pits used in West Africa, suggesting an African origin for the method we used.

Michael Bomford provides research and extension services related to organic agriculture and small-scale renewable energy production through Kentucky State University's Land Grant Program. He thanks John Clay, Harold Benson, Eddie Reed, Hank Schweickart, Brian Geier, John Rodgers, and participants in KSU's Limited Resource and Minority Farmer Conference for their help with building the sweet potato storage pit at the KSU Farm.