Improved Tunnel Technology

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When high tunnels first came on the scene, the structures were rather simple and lightweight and couldn’t handle much snow. Today, high tunnels are not only larger, but also sturdier than their past counterparts, and they are garnering attention from virtually all growers.

Three Tips For Successful Production

For successful high tunnel production, Mark Davis of Atlas Manufacturing recommends growers do the following:

1) Choose a structure that fits the wind/snow loads for a given area.

2) Use ventilation options that help to provide the best possible air circulation.

3) Consider eave or sidewall heights that would allow the use of equipment so that all usable space is available inside
the structure.

American/Western Fruit Grower caught up with several suppliers and manufacturers of high tunnels to find out where they think the future of the industry is headed and how technology changes will enhance high tunnel production.

According to Mark Davis, owner of Atlas Manufacturing, today’s high tunnels should be classified as two distinct products. One is a small, single-bay structure that is typically used by the farm marketer to capture the early and late-season markets. The other is a much larger, multi-bay tunnel system that is used by commercial growers for mass production.

Multi-bay tunnels not only allow for additional production, they allow growers to get more consistent temperatures. According to Louis Charbonneau, president of Plastitech, the climate is better in a multibay tunnel, as the wind effect is not the same as it is in a single tunnel. “With just one bay you will never get the same result as a three-bay high tunnel,” he explains. “The temperatures are more uniform in a three- or four-
bay high tunnel, which is more of a microclimate.”

Today, high tunnels are available that feature higher roll-up sides and roof vents for ventilation. “Unlike roll-up curtains, which can expose crops to cold air, drop-down curtains allow ventilation higher on the tunnel’s sidewalls, protecting crops,” says Barry Goldsher, president of Growers Supply.

The Future Of Film

In the area of coverings or films for high tunnels, Goldsher adds that traditional greenhouse film soon will be replaced by woven polyethylene films. “These reinforced films, such as our PolyMax greenhouse coverings, will last six to 10 years, which is much longer than traditional film. This type of covering creates diffused, uniform light, which eliminates overheating and helps create a healthier growing environment.”

Ralph Cramer of Haygrove Tunnels also says that traditional film is becoming a thing of the past since light diffusing, infrared blocking poly films are now available. He adds that more types of “specialist” films will come on the scene. These types of films will be used by growers with specific needs. For example, he says these films will be used to help a grower create an environment that will delay harvest so he can hit a specific market or reduce stem length.

Tunnel Tech’s Bill Nightingale agrees that high tunnel films will continue to evolve. In fact, he says that films of the future will adapt to the changing climate conditions, retaining heat on cold days and reducing heat on extremely hot days.

“The trick,” he adds, “will be to make the films cost-efficient.”

Rosemary Gordon is editor of American Vegetable Grower, a Meister Media Worldwide publication.

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