Produce growers test high tunnels

SALEM, Ohio – Farmers now have a cheaper way to grow crops year-round without purchasing an expensive greenhouse.

High tunnels allow producers to work the soil directly by manipulating soil and air temperatures using the energy of the sun.

“You can grow almost anything in the high tunnels – from tomatoes, spinach, cauliflower, broccoli, peas to berries, to flowers to fruit trees,” said Michael Orzolek, professor of vegetable crops at Penn State. “We haven’t found anything that hasn’t grown successfully in the high tunnels.”

Over the next five years at Penn State’s horticulture research farm, Orzolek and William Lamont, associate professor of vegetable crops, will conduct a series of growth trials in 24 research high tunnels, which are 36 feet long, 17 feet wide and nine feet high. Commercial-size tunnels are 96 feet long.

Construction costs for a commercial high tunnel run from $1,800 to $3,000, compared to $15,000 to $20,000 for a production greenhouse. Orzolek says the tunnels cost about $3 a square foot compared to greenhouse costs of $20 a square foot.

“There’s some big differences between the high tunnels and a production greenhouse. The biggest has to be the fact that farmers get to work directly with the soil. The ends of the tunnels open so farmers can drive their tractors through to work the soil,” said Orzolek.

These low technology high tunnels are single-car garage-size structures covered with clear plastic sheeting placed over the soil. The tunnels are built by stretching plastic sheeting over a tubular frame.

Three separate sheets of plastic form the roof and sidewalls of the structure. Farmers can raise the sidewalls to ventilate the area. The end walls 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 a tractor with attachments can be used inside.

Farmers can apply water or fertilizer as needed. They can use other plastic technologies inside the tunnel such as low tunnels – small, plastic covered frames. Orzolek said two people could easily handle a commercial-sized tunnel.

“The tunnels will allow small growers to be more competitive with others,” said Orzolek. “A farmer could have two to three acres and be successful.”

Orzolek also said the tunnels have an advantage over greenhouses because they are temporary structures that can be moved at a moment’s notice.

In addition to the research tunnels, Penn State Cooperative Extension agents in eight counties will operate demonstration high tunnels equipped with fertilizer injectors. The counties are responsible for purchasing the plastic sheeting and constructing the tunnel.

In western Pennsylvania, a high tunnel will be in place in Erie, Indiana and Washington counties.

Andy Muza, Erie County horticulture agent, chose producer Roberta Dudas’ farm as the test site for the high tunnel. Dudas will sell produce grown in the high tunnel at her farm market.

“Roberta has a nice setup. Her home is close to the fields, barn and the high tunnel. She also has a pond nearby for irrigation,” said Muza. “The tunnel hasn’t been put up yet because it was not delivered until late July and she just didn’t have the time to put it up then.”

Dudas hopes to have the tunnel in place by April. The Penn State researchers did not mandate what each county would grow, and Dudas hasn’t decided what to plant, but she is leaning toward early tomatoes.

“I’m anxious to get started with the tunnel. It’s always a push to get things into the ground and then to the market,” said Dudas. “If the tunnel makes all of that happen better or faster, it may be the way to go.”

Muza believes seeing the tunnel at the market will add interest for her current customers and perhaps bring new customers to the market. To see the high tunnel, visit Dudas Farm from mid-July to the end of October at 1955 W. Avonia Rd., Fairview, Pa.

For more information or supplies needed to build a high tunnel, visit the Center for Plasticulture’s Web site at http://hortweb.cas.psu.edu/plastic/.