Hoop Houses
Extending Growing Seasons and Crop Options for Farmers
by Lisa Ludwigsen
Perhaps you’ve noticed them while driving past a stretch of farmland—large structures covered with heavy-duty plastic. Hoop houses, also known as high tunnels, have become a popular alternative to traditional greenhouses, which utilize traditional glass or plexiglass panels. Whereas greenhouses are typically used to grow food or plants in pots or raised containers, the lightweight tubular construction of hoop houses offers more affordable and flexible options for growing food directly in the ground. A relatively low-tech tool to extend the growing season and provide a more secure local food supply for small farms, hoop houses are proving to be a real game-changer.
Small-scale farmers, homesteaders, and even backyard gardeners across the country, in all climates, are installing hoop houses to increase productivity and expand their selection of crops. Large models can cover as much as 6,000 square feet, accommodating a tractor inside to till the soil. Smaller models can be fit into tight spaces and disassembled or relocated to allow flexibility of planting schedules and land use.
Imagine harvesting baby lettuce and spinach from the ground when the temperature outside is 10°F and snow covers the ground. With a little assistance from a wood stove or propane heater, heated hoop houses can allow cold-climate farmers to grow food in the ground year-round. Even without a heating element, they are effective growing season extenders, helping farmers in all types of climates get both an early start and more time to grow into the fall and winter months.
In traditional organic farming, seeds or seedlings are planted in the field as soon as the last frost has passed and the soil is not overly wet. Depending on location, that last frost could be April 1 or even May 30 in some areas. The growing season continues until the first hard frost, which kills most annual crops. In Northern California, a killing frost typically occurs in late November. At season’s end, fields are either planted with cover crops to provide soil nourishment over the winter, or they are left fallow. The farmer then moves on to winter projects like infrastructure work or planning for the following year. So goes the cycle of farming.
Getting a few weeks’ jump on the growing season can mean a significant financial boost for small farms. This is where hoop houses really shine. Mendocino County’s cool, wet springs can often prevent farmers from getting crops into the ground, because working in wet soil can severely damage soil structure, often with long-lasting consequences. A large hoop house allows row crops to get into the ground early, and controlling the temperature inside gives the plants a comfortable, healthy start. As the season progresses, the hoop house sides can be lifted to allow adequate air flow and temperature control. Hoop houses also provide protection from environmental factors like damaging hail or high winds (though severe weather can damage the house).
With an average summer temperature of just 65°F, the Mendocino coast has its own, rather unique, agricultural challenges. Though cool weather crops like lettuces or brassicas thrive in a cool coastal climate, growing tomatoes or other heat-loving summer crops presents considerable hurdles. Nye Ranch in Fort Bragg utilizes hoop houses to grow summer crops and flowers for their popular farm stand and farmers market customers. Hoop houses deliver reliably warm temperatures and help control moisture which can promote blight, mold, and other unpleasant plant diseases.
“We couldn’t grow tomatoes on the coast without the hoop houses” said Shea Burns, owner of Nye Ranch. “They don’t like the direct salt air.” The covered arches also protect against the late rains. “This year, because of the protection these provide, we were able to beat the inland farms to market with the first tomatoes,” Shea elaborated. “We also grow bell peppers and basil in ours.”
They even have one one hoop house used as an “experimental tunnel.” Shea explained, “We’ve been growing flowers in that one. The late rains damaged many of the blossoms that were growing outside the hoop house, but those inside were protected. [The hoop houses] allow us to overwinter some crops while planting the rest in a cover crop to renew the soil.”
Just a few miles inland as the crow flies, farms deal with different weather extremes, as summer temperatures regularly reach into the high 90s and hard frosts can occur even in late spring. Jessie Taaning-Sanchez of Inland Ranch in Redwood Valley says that the hoop house she borrowed from another farmer allowed her to stay ahead of the game at the start of the growing season. “I have my tomatoes started under the hoop house and so I got a head start even when a hard frost hit in late April. This was easy to pop up and get my plants in.” Later in the season, when the temperatures rise, shade cloth can replace the plastic, or the plastic can be removed entirely.
Chris Duke, owner of Great Oak Farm in Mason, Wisconsin, utilizes a collection of hoop houses to keep his 40-acre farm productive all year. “We start seedlings inside our small greenhouse in early spring and then plant directly into the ground in our large houses,” he shared. Planting in hoop houses allows Duke to grow tomatoes, cucumbers, and peppers in a very short growing season, as well as harvest some crops in the dead of winter. “We can get into trouble if there is too much wind or if heavy snow accumulates along the edges of the hoop house, but in general they are a great assist in our cold northern climate,” he explained. Duke’s farm supplies a year-round CSA based in Wiscon-si’s Bayfield and Ashland counties. In winter, the CSA relies on stored staple crops like beets, potatoes, onions, carrots, as well as frozen meats and value-added products, but fresh produce is a big bonus for those supporting local agriculture all year. Duke added, “We also really value our employees and want to keep them on the payroll, so we don’t want to shut down production in the winter. The hoop houses keep us going.” Northern California farmers rarely deal with the drastically cold conditions found in far northern climes, but Mendocino County’s wildly variable geography presents its own challenges, and local farmers are also seeing the benefits of hoop house farming.
Of course, there are a few concerns about hoop houses. Primarily, that’s a lot of plastic, and when it breaks down, disposal is difficult. Another concern is that insect infestation, once established in a closed hoop house system, needs to be addressed quickly.
The USDA has recognized the effectiveness of hoop houses on small farms. They are offering grants through the Natural Resources Conservation Services program, with the focus of the grants on soil health and erosion prevention. Planting directly into the soil is a requirement, which is perfect for the design and function of hoop houses.
Supporting a network of small food producers at a national level is an encouraging development for the stability of regional food supplies. For anyone interested in building a high tunnel/hoop house—even backyard gardeners—YouTube is filled with firsthand stories and advice. Or take a drive around Mendocino County and check out the hoop houses in use. They’re hard to miss, and though they’re not particularly lovely, they will help provide us with farm-fresh produce well outside of the traditional growing season.
Top article photo courtesy of Nye Ranch. Additional photos by Lisa Ludwigsen.
Lisa Ludwigsen is a writer and marketer working with food, farms, and family small businesses throughout Northern California. She has worked in organic agriculture, natural foods, and environmental education for over 20 years.