How 'high-tunnel agriculture' helps Untiedt’s Vegetable Farm near Waverly extend the growing season
Editor's note: This article is part of Home grown, a feature appearing in the July 2013 issue.
Minnesotans will long remember the stubbornly late-arriving spring of 2013. But even with snow and cold that hung on past mid-April, Jerry Untiedt had much of his tomato crop planted by late March.
That's because for more than 30 years, Untiedt's Vegetable Farm near Waverly has practiced high-tunnel agriculture: a technique developed in Europe using light-dispersing plastic tunnels to create ideal micro-climates for growing.
On the farm that Jerry and Sue Untiedt founded in 1971, about 25 acres of crops are sheltered by the high, arched tunnels, built with simple metal frames and plastic designed to diffuse light. "I'd love to say this has all been done in a scientific manner, but a lot of it has been trial and error over the years," admits Untiedt, who started with smaller 12- to 14-foot-wide tunnels and now uses structures that are 24 feet by 500 feet.
The tinkering was done under duress, he notes. "We've been subject to just about every variable Minnesota could throw at us, from late-season snowstorms to very high winds to episodic rain events."
By keeping the tunnels closed early and late in the growing season to trap the sun's heat, Untiedt has extended his growing season by at least six weeks.
He also applies pre-season soil amendments (worm castings, compost, and manure), raised-bed construction, drip irrigation, and mulch coverings. To pollinate plants, bumblebees are used in place of regular honeybees in the tunnels because of their non-aggressive nature and ability to thrive beneath the plastic coverings.
The tunnels require some maintenance, such as hourly snow removal during winter storms - no small task. But they remove some of the risk related to Minnesota's capricious weather, Untiedt notes. By mid-June, he's picking his first tomatoes.
Judicious selection of plant varieties is another way to extend the growing season. One of Untiedt's newest fruit varieties is "day neutral" strawberries, which can be harvested until the end of October.
During the early years, Untiedt's farm was a "marginally profitable" operation selling mostly to wholesalers in the Twin Cities. With seasonal cash flow limited to a few months a year, Untiedt quickly realized he needed to expand his crop offering and began building greenhouses to grow flowers and other bedding plants.
Marketing directly to the public through farmers' markets and CSA has been a successful strategy.
"We do our very best to build relationships with the people who purchase and consume our products," says Untiedt, whose customers also include retailers such as Kowalski's, Coborn's, and Jerry's Markets, along with a few Twin Cities restaurants.
In addition to the sheltered crops, the farm also grows vegetables, grain, and soybeans on uncovered land.
Untiedt's Vegetable Farm
Leadership: Jerry Untiedt, owner; Paul Nelson, head grower
Employees: 12 full-time, 150 seasonal
Revenue: "Low 7 figures"
Description: Grows and markets biologically sustainable fruits and vegetables, as well as commodity crops