UNIVERSITY PARK, Pa. -- Buying fresh local tomatoes in June or July and cultivating spinach and other leafy greens year-round could become a reality if farmers adopt a low-cost, low-tech, high-quality, high-yield plastic technology called high tunnels, according to a team of researchers in Penn State's College of Agricultural Sciences.

"High tunnels can be used as a side enterprise to a larger farm operation, or you could start a large operation using four to six commercial-size high tunnels," says William Lamont, associate professor of vegetable crops. "You can use these for gourmet or specialty crops, or for organic farming. You even can put small fruit trees such as figs inside the structures."

Explained simply, high tunnels are single-car garage-size structures covered with clear plastic sheeting to manipulate soil and air temperatures using the energy of the sun. Over the next five years at Penn State's horticulture research farm, Michael Orzolek, professor of vegetable crops, and Lamont will conduct a series of growth trials in 24 research high tunnels, which are 36 feet long, 17 feet wide and 9 feet high.

The structures are built by stretching plastic sheeting over a tubular frame. Three separate sheets of plastic form the roof and sidewalls of the tunnel. Farmers can raise the sidewalls to ventilate the structure. The endwalls are constructed so the one-piece section has a doorway, but it also is designed so that two people can lift the section and place support poles under it so that a tractor with attachments can be used inside.

As temperatures drop in the fall, farmers can use other plastic technologies inside the structure such as low tunnels (small plastic-covered frames shaped like a Quonset hut), floating row covers made from various plastic polymers, and thermal covers, which use reflective surfaces to trap heat around the plants at night.

Orzolek, Lamont and other researchers currently are conducting growing trials for a variety of vegetables, including tomatoes, peppers, potatoes, spinach, lettuce, okra, ornamental gourds, cauliflower, raspberries, blackberries, strawberries and cut flowers.

Commercial-size versions of high tunnels, which are 96 feet long, also protect plants from insects, diseases and wind damage, virtually eliminating field loss, which can run as high as 25 percent for some crops. Construction costs for a commercial high tunnel are from $1,800 to $3,000, compared to $15,000 to $20,000 for a production greenhouse.

High tunnels have been used in Europe and Japan for decades, but Lamont says Penn State has the largest high tunnel research program in the United States.

In addition to the research tunnels, Penn State Cooperative Extension agents in eight counties operate demonstration high tunnels. Within the next three years, Orzolek and Lamont hope to complete a high-tunnel operating manual for producers that can be printed or posted on a Web site.

"These things really should be called Economic Development Units," says Orzolek. "You can grow such a wide range of horticultural crops, even producing 12 months a year. They can give increased income to growers through specialty farming."

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EDITORS: To contact Michael Orzolek, please call 814-863-2251. To contact William Lamont, please call 814-865-7118.

Contacts: John Wall jtw3@psu.edu 814-863-2719 814-865-1068 fax