Building a Sustainable Foundation for the Local Food System: An Evaluation of Heating Systems in Vermont Greenhouses

Industrialized agriculture has long controlled the global food supply. Environmental degradation and food security concerns resulting from the industrial system have begun to elicit a response from consumers, who are increasingly demanding local and sustainable options. A strong local food system is developing in Vermont, but ensuring that it is also sustainable presents a challenge for the industry. The state is characterized by cold and dark winters, and growing food under these conditions is an energy-intensive process. Despite the difficult conditions, about 36% of vegetables consumed in Vermont are local. Most of these are produced during the summer, when heating is not required. Research on different heating methods was conducted via a literature review and an Internet survey of Vermont greenhouse operators. The survey found that the majority of Vermont greenhouses have polyethylene film construction and heat with propane. Most Vermont greenhouses operate during the spring and summer, with just a few growing year-round. Efficient, economical, and environmentally sound methods for heating greenhouses are needed to ensure food security and sustainability. Some methods include utilizing waste heat sources, transitioning to biomass heating, and energy conservation. Recommendations for encouraging these changes include a dedicated website and newsletter for greenhouse operators, regular workshops, and development of an internet-based waste energy marketplace.