Gardeners love the flavorful tomatoes they nurture for a few weeks each summer, but they’d be astonished at the growing season in Owatonna.

There, beneath 24 acres of glass just outside the southern Minnesota city, each plant produces fresh tomatoes for about 27 weeks in a row. It’s the home of Bushel Boy Farms, where year-round production yields 12 million pounds of vine-on and beefsteak tomatoes destined for major supermarkets in and around Minnesota.

“We can put a tomato on your plate right here in Minnesota year-round that you know is safe, wholesome and will taste like a garden tomato in January,” said Keith Kersten, Bushel Boy's CEO.

The greenhouse farm is riding a wave of success as the popularity of locally grown produce has become a nationwide trend. A pioneer in extending the growing season in Minnesota, the private company does not release sales figures, but in 2015 it added a 4-acre greenhouse to its older system, and plans to build another 4 acres this summer.

Rick Steigerwald, vice president of fresh foods for Lunds & Byerlys, said his company started partnering with Bushel Boy in 1995, when year-round tomatoes grown in Minnesota were “pretty unheard of.”

“They were ahead of their time,” he said. “They’ve done a great job building a brand around locally grown, but also what really made them successful over the years is the quality and the taste.”

Steigerwald said it’s unusual in the produce industry to have a brand, which he credits to the vision of Bushel Boy’s former owner Jay Johnson.

“Where Jay was also way ahead of the curve was that he wanted to be close to market,” Steigerwald said. “Their trucks go right from the greenhouses direct to our stores, and you can’t get much fresher than that unless you grew it in the store.”

That’s easier said than done.

Making it work

The farm uses a half-million gallons of water each week in a closed-loop, drip irrigation system to avoid waste. Depending on the time of year and sunlight, zero to 18 hours of overhead electric lighting is needed each day to optimize growth. And the temperatures are controlled to range from 62 degrees at night to 72 degrees during the day.

In the greenhouse complex, the company’s 80 employees string up vines as they grow longer, intersperse new plantings with older vines, monitor insects, crop the flowers to only small clusters at the top of each plant, and harvest the tomatoes at near-peak ripeness so they can be sorted, packed into boxes, and delivered to grocery shelves. Also part of the workforce are hundreds of bumblebees that are dispatched daily to pollinate the flowers.

The goal is to maintain a delicate balance: controlling heat, humidity and light inside — while adjusting to Minnesota’s changing seasons and weather outside — to maximize tomato growth and maturity.

The tomatoes are not genetically modified and they are not organic, said Kersten, and come from varieties that have been around for 30 years.

Bushel Boy was founded in 1990. Kersten and other investors purchased it in late 2011 and have modified and expanded the system, driven in large part by consumer preference for local produce, said company President Steve Irland.

“Coming out of retail as I did, there’s lots and lots of evidence that customers will pay for superior taste, a higher degree of freshness, or a greater degree of consistency, more often in the produce department than they would anywhere else in the store,” Irland said.

Vine-on tomatoes sold usually in clusters of three or four “have taken the nation by storm,” said Kersten. “Ones that have the vines, especially with the big fuzzy stems, it’s like a neon sign saying ‘fresh, fresh, fresh,’ and everybody wants fresh today.”

Customers beyond Lunds include Cub Foods, Kowalski’s, Target, Whole Foods and some food service wholesalers.

Growing trend

Suzanne Thornsbury, branch chief for crops at the Economics Research Service, an arm of the U.S. Department of Agriculture, said that greenhouse cultivation, especially for high-value tomatoes, has been growing rapidly during the past two decades.

Fresh tomatoes from greenhouses sold in U.S. groceries went from negligible in the early 1990s to nearly 40 percent by 2005, according to one study, she said, and have seen strong growth since then. It’s difficult to get data on greenhouse production, Thornsbury said, but it’s clearly expanding.

“It’s becoming a bigger part of the fresh fruit and vegetable supply chain,” she said, “both where the traditional field production took place, like California and Florida, but also in a lot of new areas as well.”

The reasons include improved greenhouse technology and better-tasting tomato varieties, she said, and the ability to closely control water use, nutrients, pests, sunlight and cooling.

That all costs money, said Bushel Boy’s Irland, but there are savings as well, especially in transportation that can add 25 to 30 percent to the cost of produce if it comes from coastal or foreign markets.

Even so, there are cheaper tomatoes in local markets that come from greenhouses in Canada, Mexico or other countries, Irland said.

Those tomatoes were packed into boxes while green, trucked to warehouses and distribution centers, and gassed with ethylene to hasten their ripening.

It can take three weeks from when they were picked for those tomatoes to make it to grocery shelves, he said.

Hikaru Peterson, an applied economist and professor who works in consumer food marketing trends at the University of Minnesota, said the popularity of locally grown food has been growing significantly for at least a decade. Bushel Boy has benefited from already being there to fill that demand, she said, and others are following.

Some growers are experimenting with less expensive alternatives to greenhouses that can extend the growing season by several weeks, Peterson said. They include hoop houses covered with plastic instead of glass, deep winter greenhouses that collect heat with passive solar systems or sheltered systems built into the side of hills or against barns to reduce heating expenses.

Mary Rogers, assistant professor of horticultural science at the University of Minnesota, said that locally grown foods during the summer have become so popular and well-established that it’s difficult for beginning growers to get into the market.

“Winter is kind of the new frontier,” she said, and more producers on a small scale are starting to grow into the winter season.

Steigerwald from Lunds & Byerlys said that Bushel Boy has set a good example because of its quality, and warned that taste and flavor are all-important for success.

“Even if it’s local,” he said, “if it doesn’t taste as good as you would expect, that’s not going to cut it. Consumers won’t take to it, and it’ll just go away.”