CANDO (AP) - Tucked among rolling fields of wheat, canola and sunflowers, six acres of garden produce cover a hillside just south of this town. It might be the last place you'd expect to find row after row of ripening cabbage, but Mike Johnston's been at it for years.

"We started in 1997 with a raised bed trial. We had carrots, onions, sweet corn and some Chinese cabbage," he remembers, "but it was more of a test plot."

Now Johnston's crop includes cabbage, squash, pumpkins and radishes. He says raising the produce is far more time-consuming than planting and harvesting his other 1,500 acres of corn, sunflowers, durum and hard wheat.

"Oh it's much, much more labor intensive," he says good-naturedly.

When asked if it's worth the extra effort, he pauses then acknowledges with a laugh, "We're not sure."

Turning serious, Johnston explains, "Actually, we're trying to go to more of a high-value operation. Instead of increasing farm size in terms of acres, we're trying to increase the value per acre."

He is quick to point out that a higher return usually mean higher expense, which, in turn, increases risk.

"What we're trying to determine, even after six years is, is this something we can slowly expand?" he says thoughtfully.

Some crops have worked well, others not so much. Johnston says it isn't just a matter of learning what grows well on your land, but also who is willing to buy it.

"Zucchini's a gray area, as far as value," he says. "We do have some of it, but not many people admit to that," he chuckles, referring to the squash's commercial value.

This was the first year Johnston tried larger-scale radish production, and he seems pleased with that crop.

"We might do a little more with the radish and see how it goes, if we can fit in," he says, referring to the amount of time he's already spending with his other produce crops.

"You have to have an idea where your product is going to go," Johnston continues. "Even a good-quality product sometimes isn't enough to get it into the marketplace."

Currently, the bulk of his produce goes to a wholesaler in Jamestown who, in turn, distributes it as far west as Williston, as far south as Aberdeen, S.D., and eastward to just outside the Red River Valley.

Johnston says he's recently started trucking some of his own produce to Grand Forks grocery outlets, which prompts him to share a humorous story.

"The first year that we did this with any volume, we did haul some to Fargo, but it was funny because we used a grain truck," he laughs. "Here come all these refrigerated trucks and semis with all their chrome, and then here's this farm truck backed up to one of the doors."

Johnston begins investing time and care in his produce crop, even before the growing season really has begun.

His plants start out as seedlings inside a greenhouse he purchased in Cando. They later are transplanted into the field with a machine that pokes holes into rows of plastic-covered earth and slips them one by one into the dirt. It's a process that takes about four days.

Once in the ground, the tender plants are nurtured with drip tape irrigation. Water for the system comes from a nearby pond and is strained through a standard pool filter.

"It's just not a big enough area to justify a big stainless steel commercial filter that would have cost us five or six times as much," Johnston says simply.

Johnston is one of 10 Devils Lake-area farmers hoping to learn more about irrigation and its effect on the basin area.

A North Dakota State University study, examining the way irrigated water moves through the glacial soils of northern North Dakota, is under way.

Wading through a sea of 6-foot-high corn, Johnston shows off the data collection equipment researchers have placed on his farm. Precipitation and soil moisture are measured on a regular basis throughout the growing season.

Back in the cabbage field, Johnston uses a customized European vegetable harvester to bring in his mature crop. Though it's a big machine, the actual picking process still is done by hand.

Harvesters walk along the rows, plucking tight cabbage heads from the surrounding leaves and dropping them onto the machine's conveyor.

After harvest, Johnston and his business partner bring their crops to a finishing facility on his partner's farmstead. Inside the cool, dark building, seasonal employees inspect and sort the freshly harvested cabbages.

Some are boxed and shipped out for sale as head cabbage. More irregular heads are boxed and shipped off for shredding.

"In wheat, you cut everything, and there's a fairly high percentage that's recovered, but with something like cabbage, you never get 100 percent. I'd say over three-fourths of what we plant is harvested," Johnston said.

While most of his produce is marketed through a wholesaler, he's also a big fan of farmers markets and participates in the Devils Lake Community Market. He says selling to friends and neighbors is a good way to research the market.

"One of the reasons we continue to do that is you get that immediate response from people," he said. "They can see it, look at it - it's more direct than when you sell it to a wholesaler."