A John Deere Publication

Long greenhouse under bright sun; rural landscape

An underground greenhouse provides a year-round oasis of green and fresh eats, including citrus straight from the tree.

Agriculture, Specialty/Niche November 01, 2025

A Bit of Zest

Underground greenhouse keeps prairie life fresh.

Story and Photos by Martha Mintz

It's late fall on the southeastern Montana prairie. The days are hot and dry, the nights cold, and the wind an increasingly constant companion. While the outdoor gardens are done and the green long leached from rangeland grasses, the Barkley family reveals a secret stash of summer.

Their geothermal underground greenhouse gives them a Zone 8 escape from a Zone 3B existence where temperatures routinely drop to -30, even -35 degrees. Twelve-year-old Haddie can pop into the greenhouse anytime she likes, nabbing lemons and limes that she eats rind and all. It's certainly a novelty on a century farm built on cattle and small grains.

Haddie's parents, Molly and Todd, built the greenhouse in a bid to diversify income. It wasn't their first choice. They tried to purchase a meat processing facility to market their own beef and hogs. Covid put an end to that deal, though they do still market meat direct to consumers.

Discovering a Nebraska company selling geothermal, four-season greenhouse kits pushed them in a new direction. They figured they could grow fresh food for themselves and maybe market surplus in their extremely remote and isolated community.

"We're producers. We like to grow, so why not?" Molly says. She was also sick of grasshoppers eating her garden, making the greenhouse appealing on many fronts.

The Barkleys built the greenhouse during the summer of 2021.

"It was a 100-year drought so we didn't have any hay to put up or crops to harvest anyway," Todd says. Yet another reason to develop additional income streams.

They trenched the greenhouse into a hillside, burying tubing 12-feet deep to circulate temperate air for climate control. They're able to keep the 82-foot long, 17-foot wide, and 12-foot tall growing area at least 35 degrees through winter...most of the time. Sometimes Montana throws a -40 degree day as a curve ball.

"We've only used supplemental heat five times in four winters," Todd says. Water tanks and ledges of beds stair stepping down to the dirt floor act as heat sinks, helping to stabilize temperature. Shade cloth tempers the intense summer sun. Outside temperatures can climb well over 100 degrees.

Above. Molly, Todd, and Haddie Barkley enjoy spending time in the greenhouse. It should eventually generate enough produce to add to their Barkley's Home Grown lineup of beef, pork, honey, and syrup.

Growing fun. Citrus is their primary focus. They planted semi-dwarf lime trees capable of producing 150 limes each. Next came lemons and clementines. Then, excitement got the better of them. They planted pomegranate, pear, and peach trees.

"I over ordered. I thought we'd lose more trees than we did," Todd says. Of 20 trees, the citrus are doing well, but others might have to go. "The peach blooms in February. It smells so good, but it isn't a great time for pollinators."

While they wait for their citrus grove to mature, they filled the greenhouse with everything else imaginable and take great joy in experimenting.

"I love researching what we can grow and trying exotic plants," Molly says. Three-year-old tomato vines with tree-trunk bases reach the roof. Celery, garlic, and kale grow perpetually. Cucumber vines climb throughout and plants are allowed to volunteer. Every nook in the jumbled jungle has something growing.

The greenhouse is its own ecosystem. Ladybugs handle pests and earthworms work the soil.

"Haddie has toads and brings her turtles in here. She loves to feed them the worms," Todd says.

They've sold some surplus produce, but so far the greenhouse is more escape than business.

"Some people buy an RV or a lake house, we got a greenhouse," Todd says. It truly does help with morale. Even their hired hand, Kendyl, seems to enjoy time spent maintaining the plants.

The Barkleys have crunched the numbers and still see economic potential. "Like growing a shelter belt, these things take time. This may well be our retirement project," Todd says. ‡