Leopold Center for Sustainable Agriculture

High tunnel resources for Iowa growers

Back to Leopold Letter Spring 2012

By MELISSA LAMBERTON, Communications research assistant

Imagine fresh, local raspberries at Thanksgiving dinner.

Fruit and vegetable growers can extend the growing season with high tunnels, plastic-covered, greenhouse-like structures that yield high-quality produce in a limited space. Linda Naeve, Extension program specialist with Iowa State University Extension’s Value Added Agriculture Program,  and other ISU specialists have developed new resources to teach growers how to use high tunnels to improve the profitability and sustainability of farms.

To date, funding from the Leopold Center’s competitive grant program has produced two high tunnel publications, supported five workshops and trained 179 fruit and vegetable growers in Iowa.  The investigators received additional funds from the Iowa Department of Agriculture and Land Stewardship (IDALS), Sustainable Agriculture Research and Education (SARE) and ISU Extension and Outreach to support a total of 12 workshops around the state in the past three years.

“There’s currently a lot of interest and a high demand for information on growing fruits and vegetables in a high tunnel,” Naeve said. “Many people tell me, ‘I thought about doing that, but I just didn’t know how to get the whole system to work efficiently.’”

Growers can produce a crop four to six weeks earlier inside a high tunnel, and extend the season longer in the fall, which helps them earn premium prices for produce like raspberries. High tunnels also improve the farm’s sustainability through controlled nutrient and water management.

Naeve, Henry Taber, retired extension vegetable crop specialist, and Paul Domoto, extension fruit specialist, experimented with growing crops in high tunnels with a competitive grant from the Leopold Center’s Marketing and Food System Initiative, awarded in 2007. They found the most profitable business plan was to grow multiple crops per year and carefully control the environment inside the high tunnel. They developed financial reports (available on the Leopold Center website) for certain high-value crops, including tomatoes, peppers, pole beans, raspberries, blackberries and Greek oregano. They also experimented with cucumbers and tulips.

With a second grant from the Marketing and Food Systems Initiative, the investigators continued offering introductory workshops and developed the Iowa High Tunnel Fruit and Vegetable Manual (PM 2098), a comprehensive workbook for growers. It is available from the ISU Extension Store in both English and Spanish.

“Several of the people we first trained with the manual are putting up their second tunnel now,” Naeve said.

Susan Jutz, owner of ZJ Farm near Solon and a member of the Leopold Center’s Advisory Board, constructed her first high tunnel a decade ago. Now she has a second, movable high tunnel that she can use in early spring, throughout the heat of the summer and into autumn. “Last spring without our high tunnels we would not have had an adequate supply of vegetables to support our spring share,” Jutz said. “With our moveable tunnel we supplied 110 families with vegetables for five weeks from late April to late May.”

“I can’t imagine being without a high tunnel, frankly,” Jutz added. “I love my high tunnels.”

According to Jutz, field days and demonstration projects are vital ways to introduce growers to new options.  She has begun to make improvements to her original high tunnel to bring it up-to-date to the latest research. She also has visited the ISU Armstrong Research and Demonstration Farm near Lewis to take a look at Naeve’s latest project: developing a prototype gutter system that catches, stores and reuses rainwater.

Rainwater sheeting off a high tunnel’s curved roof can cause problems with erosion and soil saturation. The gutter system addresses these issues, while simultaneously supplying irrigation water for the crops inside the high tunnel. Naeve and Shawn Shouse, Extension Agricultural Engineer, recently completed the prototype system with funding from the Leopold Center’s Ecology Initiative.

Growers interested in learning more can download a seven-page fact sheet, Rainwater Catchment from a High Tunnel for Irrigation Use (PM 3017), from the ISU Extension Store or Leopold Center website.

The USDA-NRCS Environmental Quality Incentives Program (EQIP) currently offers a Seasonal High Tunnel Initiative, which provides financial and technical assistance to growers interested in constructing high tunnels. The three-year pilot program will end this year. For details about how to apply, visit www.nrcs.usda.gov  or call your local NRCS office.

Back to Leopold Letter Spring 2012