Thermal Banking Greenhouses

At Minnesota’s latitude, farmers who can extend their growing season have a distinct advantage in the marketplace: By offering a product outside the “normal” growing season, they can often receive a higher price. That’s what Steven Schwen (Earthen Path Organic Farm) has done with his greenhouse, starting earlier in the year with seedlings of warm-season vegetables, and continuing production into the fall and even the winter months when he grows cold-tolerant crops. Part of what makes Schwen’s operation so unique is the added innovation of thermal banking, which significantly reduces the energy costs of running a greenhouse for cold-season production.

As Schwen describes in this video, thermal banking is the storage of heat that accumulates during the daytime, especially on sunny days. That heat can then be used to keep the greenhouse beds warm during cold periods. Schwen’s thermal banking greenhouse is a key component of his farming operation, particularly in this time of global climate change and energy insecurity. He feels this project moves him closer to his ultimate goals of energy independence and self-sufficiency. SARE’s Farmer-Rancher Grants program provided critical assistance for Schwen in the beginning phases of his project.

Download Schwen's drawings and design specifications for thermal banking greenhouses:

Want more information? See the related SARE grant(s) FNC99-256, Year-Round Renewably Heated and Powered Greenhouse.