The Gift That Keeps on Heating

Farm-to-table energy from compost.

“Our soil is powered by compost,” reads the sign on Stone Barns Center’s dooryard garden gate, a reflection of our core philosophy about farming. The idea of using compost as the primary nourishment for soil is the fundamental tenet of sustainable agriculture and the main alternative to conventional chemical applications.

Compost is powerful, and in more ways than one: It generates heat. In a new experiment underway at Stone Barns, we’re devising a system that will harness the heat from compost to power unique opportunities for Blue Hill at Stone Barns, our onsite restaurant partner.

Four Season Farm Director Jack Algiere and his team are constructing a 300-square-foot growing space in a stone shed at the back of Blue Hill, whose centerpiece will be a compost bin that serves two distinct functions. One area will capture high heat for a variety of experiments, and in another area, lower heat will power the growth of
sprouts and micro greens used by Blue Hill chefs in their direct-to-table creations.

In this system, heat is generated by the breakdown of organic material inside the compost bin, which, in this case, will contain seasonal vegetable scraps, grasses and leaves. This naturally occurring process is sped up by forced air blown into the bin, which creates a high temperature of 160 degrees Fahrenheit. Heat is then captured by a large copper coil filled with water, which flows into a system of pipes that circulate through the high-heat section and then run along seed germination racks at lower heat. In this closed-loop system, the water is continuously cycled back through the original compost heat source to be reheated and recycled through the pipes.

The project takes into consideration both the farm’s and the restaurant’s needs for heat and uses a single source—compost— to meet them both. It turns an outbuilding into a propagation, dining and learning space. The construction is modular, and the compost bins are mobile and interchangeable. “Think about how many uses there are for heat,” says Jack. “The possibilities are endless.” His hope is that these pieces will move around the farm as more radiant-heating systems are created for any number of purposes—growing, incubating, even cooking—creating one big plug-and-play system built on the humble power of decomposing vegetable matter.