By Tom Burfield
When grower Timothy Bradford plants bell peppers in an open field on his Isola, Miss., farm, an early frost can bring his fall deal to a halt as early as the first week of October, and he can’t plant his spring crop until after mid-April.
Now, thanks to a high-tunnel growing structure that he built last year, he can harvest bell peppers as late as December and do his spring planting in February.
Photo courtesy of the Mississippi Agricultural and Forestry Experiment Station
Tunnels or hoop houses are tent-like structures made from plastic stretched over a skeleton. They trap daytime heat and minimize the amount lost during the night.
High tunnels—or hoop houses, as they’re sometimes called—have been around for years. But the need for growers to enhance their profits in a down economy coupled with the current consumer craving for locally grown produce has sparked a resurgence.
“Growers are trying to figure out how they can produce high-quality produce, sell it locally, direct market it and get the highest price they possibly can,” says Bob Hochmuth, multi-county Extension agent for the University of Florida at the North Florida Research and Education Center in Live Oak. “This whole plasticulture technology fits into that perfectly.”
Tunnels are tent-like structures made from layers of plastic stretched over a skeleton often made from PVC pipes. They trap daytime heat, minimizing the amount that escapes at night, says Bill Evans, assistant research professor and research coordinator at the Mississippi State University truck crops branch in Raymond.
Tunnels are most valuable around the first frost in fall and just before the last frost in spring, he says. They’re similar to greenhouses, but they don’t have fans or heaters, and they don’t need electricity or gas.
“The one utility that they must have is irrigation,” Evans says. They typically use a drip system.
Hoop houses use the same type of equipment you would use in a field—a standard mulch layer, bed shaper and a small, single-row tractor.
The sides can be rolled up for ventilation, and the end walls open up so the tractor can get in. Evans recommends sides that can be lifted at least 4 feet—8 feet is ideal.
Any crop that can be grown in a field can be grown in a tunnel, Evans says, but growing in a hoop is more expensive, so it’s important to consider return per square foot. He recommends planting high-value crops, such as strawberries or bell peppers rather than sweet corn or pumpkins.