High Tunnels: Extending the Life of Crops in Cool Climates

Extending the growing season has become a popular endeavor for farmers as consumers seek locally produced food from sources they trust. Northeast farmers trying to grow beyond the typical season are turning to “high tunnels”— simple, plastic-covered structures that warm and shelter crops—from which they can market their crops directly to customers.

“People like to look farmers in the eye and talk to them about what they’re producing,” said Bill Lamont, a horticulturist at Penn State University who received a SARE professional development grant to inform extension educators and vocational agriculture teachers about high-tunnel technology.

High tunnels resemble greenhouses but cost much less to erect and operate. To construct a high tunnel, a farmer stretches a layer of clear plastic sheeting over a galvanized metal pipe frame, typically 21 by 96 feet. One of the high tunnel’s most useful features is its versatility: the plastic sides can be rolled up for ventilation. Using a high tunnel, farmers can add weeks, if not months, to the growing season.

Lamont conducted his first workshop at the Penn State High Tunnel Research and Education Facility, where educators have built 36 research/ demonstration high tunnels. Participants learned both about tunnel construction and growing tips for fruit, vegetables, and cut flowers. The training also covered transitioning to organic production and how to raise crops without agri-chemicals. Following the workshop, all of the 15 participants held training sessions in their counties about high tunnels and several have helped growers in their area to construct them, Lamont said. One participant, a county extension educator, built a high tunnel in Clinton County to train master gardeners.

Lamont also aims to interest future farmers in the new technology. Working with vocational agriculture teachers, he has encouraged three tunnels to be built in high schools, including one in Philadelphia. High tunnel production is ideal for urban agricultural settings, he said.

In a related SARE grant project, a Penn State researcher is testing biological control practices in high tunnels. By releasing insects that prey on pests inside high tunnels, researchers are determining whether they can control vegetable pests like spider mites, aphids, and whiteflies.

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