Tools of the Trade: Hoop houses

High or low tunnels, greenhouses or garages—hoop houses are handy structures on hobby farms.

By Jim Ruen for Hobby Farms

Photo courtesy Four Season Tools All hoop houses have steel, PVC or poly-pipe "hoops" that support a flexible cover.

I just built my first hoop house. OK, it isn’t what you might think of when you think hoop house; it’s really what’s called a low tunnel. In my case, I bent steel electrical conduit using a hoop bender from Lost Creek Greenhouse Systems. However, in all respects, my 4-foot wide, 4-foot high, Agribon-fabric-covered structure is as much a hoop house as a 30-foot wide, plastic- covered greenhouse or fabric-tension garage.

What all of these structures have in common is simplicity of design that uses steel, PVC or poly-pipe to create half-circle or “hoop” supports for a flexible cover. How the hoops are fixed in place and how the cover is secured are all that really differs. Whether covered with plastic or heavy-duty woven fabric, properly tightened and anchored, a hoop house can withstand high winds and a heavy snow load. The hoops themselves can vary from PVC pipe to steel electrical conduit to a range of steel and wood components. Using wood, concrete, gravel or earthen pads, the structures are fast to erect and low in cost compared even to pole barns. 

Photo courtesy Farmtek Hoop houses are particularly valued for their year-round food-production capabilities.

Hoop houses have already earned a home on many small, hobby and large, commercial farms alike for crop storage, livestock shelter and equipment storage. Hoop-house designs are particularly appealing for year-round food production.

“In my opinion, the hoop house is the No. 1 technology for market and home gardeners, and interest in them is exploding,” says Steve Upson, horticultural consultant for The Samuel Roberts Noble Foundation, a nonprofit agricultural research organization. Since 1995, Upson has been working with, improving on and spreading the word about hoop houses: “They aren’t new, but they are being adopted today at a phenomenal rate. Their use cuts across philosophies of growing, regardless of what inputs you use for managing fertility or disease. Everyone can use hoop houses.”

Year-round gardening expert Eliot Coleman agrees wholeheartedly. He’s been using stationary hoop houses for years to extend his market-garden production and sales season. His high tunnels, when used in conjunction with low tunnels inside, extend his normally short, Maine-seacoast growing season into a year-long endeavor without the need for additional heat production.

“High tunnels have the effect of moving the plants about one and a half [USDA hardiness] zones or 500 miles south,” he says. “Put low tunnels covered with Reemay [polyester fabric] over the plants inside the high tunnels, and we’ve moved the plants another 500 miles south.”

Coleman has modified the concept by placing interior bracing on the hoops, as well as skids or wheels on their bases, to create a movable high tunnel that he can place over an early planting of warm-season crops, like tomatoes, that would normally struggle to mature in the cool Maine summer. As they finish production in mid-October, Coleman moves the hoop house over an August-planted cool-season crop to protect it through the late fall and early winter. As those crops are harvested, beds are replanted with late-winter and early spring cool-season crops. As they mature, the hoop house is again moved to receive summer-crop transplants. The benefits of this system include the ability to rotate in-ground beds for disease control and fertility.

“The real benefit of these movable high tunnels is the flexibility,” says Greg Garbos, president of Four Season Tools. “They just make greenhouse production a different game altogether.”

Garbos has worked with Coleman to commercialize and market the movable hoop-house design. “To be movable, they have to be really rugged and structurally sound,” he explains. “As the unit is moving, you don’t want it to twist, so we add more braces than in a typical high tunnel.”

Introduced in 2009, the structures are available in a 16- by 24-foot gardener size and larger sizes for market growers. They’re catching on fast, and not just for vegetables. Jeff Bahnck and his wife, Alethea, of Bridport, Vt., have modified a 20- by 48-foot Four Season Tools movable high tunnel for their 500 laying hens. Bahnck built and installed laying boxes, roosts, feeders and waterers—all hung from the hoops and braces of the high tunnel. In the summer, shade cloth over the top and galvanized mesh on the sides protects the hens from predators of all kinds. In the winter, clear poly provides plenty of light and keeps the temperature above freezing. Special bases allow Bahnck to move the high tunnel coop laterally as well as forward and back across the field.  

“As soon as the chickens hear the tractor, they all run to the side [of the hoop house] where it is, as they know they are moving to fresh pasture,” he explains.  

Bahnck is working on special caster wheels that will make lateral moves easier. Meanwhile, Garbos is developing a turnkey, high-tunnel, Hoop Coop kit with bracing for lateral moves, a watering system and plans for wooden components.

Photo courtesy Four Season Tools The Bahncks modified a hoop house to act as a chicken tractor by suspending feeders and waterers from the structure's supports.

Tod Hanley and his wife, Jamie, can’t move any of their high-tunnel hoop houses with a tractor, but they can take down any one of their five 17- by 100-foot structures and re-erect it in about 21⁄2 hours in calm weather conditions. Hanley designed a quick-anchor system using rebar driven into the ground. The hoop ends simply slide over the portion of the rebar sticking out of the ground. Tensioning ropes attach to links on the rebar. Hanley designed a hoop bender that cuts his hoop costs in half and lets him use square steel tubing instead of the more common round steel or electric conduit. 

“We’ve tried different types of plastic and also shade cloth to cool the temperature down in the summer, something that is needed for vegetable production during Oklahoma summers,” he says.  

Hanley uses off-the-shelf components to construct his high tunnels. Many of the components come from FarmTek. Barry Goldsher, president of FarmTek, says both the demand for hoop buildings and the options available have grown tremendously. 

“The variety of hoop houses and coverings is unbelievable,” says Goldsher. “But with smaller structures, many of the components are the same, whether covered with greenhouse film or fabric. Our customers use them for everything from greenhouses to aquaculture and even as solar-powered kilns for drying wood.”

He advises anyone thinking about buying a hoop house to consider the end use in evaluating the construction materials, whether fabricating the structure yourself or buying a turnkey kit. He notes that high humidity can quickly rust poor-quality steel, even if it’s powder coated. Some steel products, including FarmTek’s Allied Gatorshield structural steel tubing, are galvanized inside and outside to prevent rusting or corrosion.

“To build a structure that will last, you need the right diameter pipes [hoops] and rafters, purlins, connectors and anchors,” says Goldsher. “The cover needs to be attached correctly so it doesn’t blow away or tear. It has to be tight. You can always buy something cheaper, but it doesn’t really pay.” 

About the Author: Jim Ruen lives, writes and works with his gardens and tree farm in the Bluff Country of southeastern Minnesota.

This article first appeared in the January/February 2010 Hobby Farms.