Hoop houses and tunnels are becoming a popular way for fruit and vegetable growers to extend their growing season, and by default, extend the number of marketing opportunities to potential buyers. Even in some of the most extreme conditions, the structures are quickly returning the investment.
Collin Thompson is the farm manager at MSU's Upper Peninsula Experiment Station in Chatham. Utilizing tunnels and hoop houses, Thompson is proving that food crops can be successfully grown even in an environment with only eighty-three frost free days, the longest day has only fifteen hours and forty-eight minutes of sunlight and receives 190 inches of snow annually.
During the first extended season, the outside temperature dropped as low as -31 degrees F on at least two occasions. Inside the hoop house and under several layers of plastic, the temperature dipped to 16 degrees, nearly a 50-degree difference from the outdoor temperature. Layers of protection is enough to keep tolerant vegetables growing and collects enough solar heat to plant cold tolerant vegetables much earlier in the spring without the use of supplemental heat.
If season length can be extended there, benefits can certainly be obtained in the more temperate conditions of southwestern Michigan and northern Indiana.
Thompson uses tunnels or multiple layers of plastic covering inside a hoop house which provides flexibility to adjust the number of layers as temperature and sunlight conditions demand.
For the hoop house, a gothic shape is best at repelling snow loads over a Quonset design.
Row covers or low tunnels can utilize different weight covers that will provide anything from frost protection to deep winter protection.
"Surprisingly, overheating can become a problem," Thompson said.
"The biggest problem with row covers or low tunnels is the water displacement into the crop planted next to the tunnel. Mold is something you have to keep an eye out for."
Mike Bollinger of Decorah, Iowa discussed how their small acreage, high intensity farm quickly grew into providing a full-time living for himself and wife, Katie, in the heart of America's Breadbasket country.
The local farmers markets, while plentiful, were very saturated.
"We began to realize that there are enormous pockets of opportunities in the wholesale markets," Bollinger said.
Forfeiting the retail premium was worth the loss to gain a stream of consistent orders and income—a big help when it comes to deciding how much to plant and when. Their micro salad greens have become the bread and butter in their farming operation.
At roughly 14 cents per square foot, the low tech and low cost of field tunnels are an incredible value when a season can be extended by up to six weeks. Reusable materials bring the costs even lower.
"The market for season extension is enormous," Bollinger said.
Moveable hoop houses can be used much like a crop rotation system. Cover crops can be used in the systems for the same purposes and results as in conventional cropping systems. Poultry, rabbits or other small livestock can also be incorporated into the rotation, depending on management.
A combination of moveable hoop house systems and tunnels can provide an opportunity to enter farming with smaller acreages or even bring a family member into an existing operation.
Thompson works to train people how to use hoop houses through a farmer apprenticeship program at the MSU North Farm in Chatham. Two-year training programs for novice or more experienced farmers are available through the incubator project. For more information on the farmer training program, visit http://www.msunorthfarm.org/apprentice-farmer-program.html.