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Seasonal High Tunnels Promote Plant Health, Provide Longer Growing Season





by Madi Linkenmeyer, Public Affairs Intern, July 2012Seasonal high tunnel systems create a warmer growing environment, allowing for a longer growing season and protection from outside factors like insects and wind.

February is typically a few months before Iowa planters begin to roll, but for some farmers the late winter months are the start to a ten-month growing season.

Seasonal high tunnels are designed to extend the growing season of fruits and vegetables while providing protection from outside factors like wind and insects. High tunnels improve the profitability of crops and maximize farm productivity.

A typical high tunnel will consist of a metal structure covered with a layer of plastic. Unlike greenhouses, the tunnels require less building materials and little or no electricity for heating.

Mike Schnoebelen, a high tunnel farmer in central Iowa, says his plants yield more crop and are better looking than crop grown outside the tunnels. "When you grow outside, they're [vegetables] exposed to insects, hail — a lot of things," said Schnoebelen.  

Schnoebelen has grown some crop, like spinach, over the winter months. "I've had days in the winter when it's been 85-90 degrees in the tunnel," he said. Schnoebelen is able to make use of his high tunnels all year long. 

The New Virginia producer grows vegetables in two high tunnels, one funded through a partnership with the Warren County Philanthropic Foundation and a second with funding assistance from the USDA Natural Resources Conservation Service (NRCS).

The crop from both tunnels is donated to Food for Iowa, a local charity that donates fresh produce to those in need and senior citizens. Food for Iowa began in 2009, and has since delivered more than 13,000 pounds of fresh produce to central Iowa food pantries.   

Chris Ackelson had tomatoes plants more than waist high in June. Ackelson uses the profit from his high tunnel crop to help fund his college education.Another farmer benefiting from a high tunnel is Chris Ackelson, a sophomore at Des Moines Area Community College. Ackelson operates two high tunnels south of Des Moines in Norwalk. The young farmer was eligible for financial and technical assistance for a seasonal high tunnel system through NRCS and now uses the profit from the crops to fund his college education.

In June, Ackelson already had ready-to-eat cucumbers and his tomato plants were more than waist high. He plans on selling his crop at farmers markets in central Iowa. 

Through the Seasonal High Tunnel Initiative, NRCS encourages farmers to promote plant health as well as take advantage of the longer growing season and high yields provided by high tunnels.

Since 2010, NRCS has provided nearly $1 million to Iowa landowners, installing more than 200 seasonal high tunnels across the state.  

NRCS funds a portion of the tunnel costs and assists farmers in developing a conservation plan. Applications are accepted on a continuous basis, and cutoff dates are established to rank applications for funding.

If eligible, producers must maintain crops for a minimum of four years. High tunnel systems are commercially available, but must meet NRCS initiative requirements.  

For more information go to or contact your local NRCS office.

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Seasonal High Tunnel Systems Promote Plant Health, Provide Longer Growing Season  (PDF, 1.7 MB)