BROOKINGS, S.D. — High tunnels are structures similar to greenhouses that are a useful tool to allow specialty crop growers across the upper Midwest to extend their growing season from early spring to late fall. Funded by a United States Department of Agriculture Specialty Crop Block Grant administered by the South Dakota Department of Agriculture and Natural Resources, SDSU Extension is hosting workshops across the state to teach participants the dos and don'ts of high tunnel building.
“We know in a state like South Dakota that the number of vegetable farms since the last census of agriculture has increased in the state,” said Kristine Lang, assistant professor and SDSU Extension consumer horticulture specialist. “But we also know that those farms have actually gotten smaller on a per acre basis, which tells us that people are downsizing their farms, are growing more intensively, are diversifying on those farms and high tunnels can be another way to accomplish that.” huge greenhouse
A two-day workshop was held May 7 and 8 at the SDSU Specialty Crop Research Field in Brookings, South Dakota, and participants were able to gain hands-on experience as they helped construct a 30-by-96-foot gothic-style, double-poly high tunnel.
Also known as a hoop house, a high tunnel is a protective structure used to extend the growing season and improve the quality of produce. An increasingly popular option for vegetable and flower growers, high tunnels offer a less expensive alternative to greenhouses. Plants in a high tunnel are still grown directly in the soil, unlike a greenhouse.
“The best way to learn how to build a high tunnel is to really show up in-person and get your hands on a high tunnel,” Lang said.
Dirk Oudman, a farmer from Blue Sky Vegetable Company near Worthing, South Dakota, assisted with the workshop as one of the farm experts. Oudman has been farming vegetables for around eight years and markets his produce through a subscription box service. Primarily a tractor-scale operation, he says they also utilize a few covered spaces on their farm which offers them cool season extension and some control over the elements in ensuring their high-value crops get to production.
Oudman estimates that he has put up around four or five of these structures and has seen many benefits in implementing them in his operation.
“Basically everything grows better in a tunnel. Just across the board you get better moisture control, better sun, you get more heat units earlier in the year so you can grow crops faster earlier. Crops are really sensitive to temperature and light so we get a lot of light starting in about mid-February, but we don't get the temperatures in mid-February to grow stuff outside,” Oudman said. “Also, we can keep the wind off our crops. Wind damage is something that it's hard to quantify because it's not like we had a big windstorm that knocked all your plants flat. Sometimes it does. But the bigger thing is that a little bit of wind blowing the plants around just takes a little bit of energy from them growing and makes them have to grow stockier, fix wounds or have leaves that break off. So it just slows those plants down a little bit. We use our covered spaces primarily for very high-value crops.”
The workshop offered the opportunity for participants to get their hands on a brand new structure, something Oudman said he was eager about as he often builds high tunnels out of used greenhouse structures he finds across the state. With a little bit of creativity, he then repurposes them in order to keep costs down for the build.
“Generally, it's not that I'm buying them in new. It's often been that we'll take one down and then we put it up somewhere else either on the same farm or we'll get one from a farm that no longer wants one and then we'll take it down and put it back up,” Oudman said. “So one of the things I was excited about for this was to use a new kit with new stuff.”
Once the high tunnel is completely finished, Lang says the next step will be several rounds of cover cropping so the soil is ready to conduct research on how plants grow in high tunnels.
arched tunnel greenhouse To learn more about educational events like this, whether in-person or on a farm, visit the SDSU Extension website .