Minimalist Approach

Great River Gardens lies north of Aitkin along the Mississippi River as it winds its way from Lake Itasca through Minnesota. Plots of berries and vegetables are grown close to the farm’s homestead, along with aspen, hay and rye crops surrounding 17,000 square feet of greenhouses. The buildings are heated with hot water from a large wood-burning boiler. The quiet river is close enough to the crops for a short walk, but not so close that direct run-off could easily reach it.

Before Joe Riehle and his family moved to the farm in the late 1980’s, it was a commercial wild rice farm. Joe’s wife Kirsten works off the farm. He has four daughters. The three oldest help with the farm work. From March to November, Riehle has five full time employees, and 15 additional part-time workers are hired seasonally. About four acres are permanently in blueberries, strawberries are grown on one acre, two acres are devoted to vine crops, five acres are in sweet corn, a variety of vegetables are grown on three acres, five acres are planted in rye for straw, five acres are devoted to aspen production, and the balance of the fields produce alfalfa or mixed hay.

Most of the farm’s produce is marketed at the farmers’ market in Grand Rapids and the garden Center in Aitkin, and hay is also sold locally.

“I’ve been using Integrated Pest Managment (IPM) since I started,” says Riehle, who is also working on a master’s degree in horticulture. He rotates fields between perennial and annual crops, which he says is “the best weed control there is,” and uses rye and other cover crops to control weeds and insects. Riehle also has studied the effects of cover crops to reduce herbicide use in strawberry establishment. “It doesn’t eliminate the need for herbicides, in my opinion, but it reduces weed pressure.”

A big part of Riehle’s management is close observation. “I don’t spray without scouting for disease or insects,” said Riehle. “I watch the weather for favorable conditions and growing times to minimize spraying. I use resistant varieties. I minimize spraying to minimize the effects on beneficial insects. I will try to mix beneficial bacteria in with the soil mix in the greenhouse to eliminate some drenching (with fungicides).” Because greenhouse conditions are favorable to root rot and other problems, which must be treated before they are readily seen, Riehle uses the beneficial bacteria before seeing any fungus problems.

In the field, “I’m spraying less frequently than I might,” he said. “It saves the cost of application and chemicals. You can definitely see the benefits from rotation and cover crops. I see improved soil structure. On alfalfa, it saves on fertilizer, too.”`

In the field, no spray is used without first observing problems. “Timing is critical,” Riehle said. Riehle has used peat from the farm to improve soils when working the land. “Mixing it with farm compost, it added organic matter and made plowing easier,” he said.

Healthy Results

Riehle has never used insecticides without first scouting for pests, and he said he sprays less frequently than he would without such observation. Improving soil structure is a major goal, and Riehle can see the benefits to the plants when soil is better drained.

In spraying for insects and fungi, Riehle estimates he can “get by with half the number of sprays you would do by the calendar.” By carefully scouting for pests, Riehle said he can also run a lower volume of chemicals through the sprayer. He said any added costs for observation are minimal. “You have to be looking at the crops anyway.”

Riehle belives his careful use of chemical sprays, along with reducing erosion and runoff, is good for the neighboring Mississippi River. “We have a pretty wide buffer strip between the fields and the river.” He says he strives “to feel like you’re doing the best you can for the environment and succeeding generations.” By using plastic mulch, Riehle often eliminates the need for herbicides and hand hoeing.

“The impact of crop rotation on weed control is pretty dramatic,” Riehle said, and the soil is easier to work. Alfalfa roots are now observed below the plow hardpan.

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This article is one in a series which can be found in “A Bountiful Harvest: Minnesota Fruit and Vegetable Growers Manage Pests,” Sept., 2002. The publication was produced by the Minnesota Department of
Agriculture (MDA) with funding provided by the U.S. Environmental Protection Agency, Region 5, Chicago, IL. For the entire article please go to the MDA’s web site at:
http://www.mda.state.mn.us/ipm/fandvipm.html