Michigan growers test onion crop management strategies through variety trials

Michigan farmers continue to refine onion crop management strategies through ongoing observation trials. The state does not rank among the top 10 onion-growing states, but growers work to improve their methods year after year.

According to the National Onion Association‘s 2016 numbers, Washington led the nation with 23,900 acres, while Idaho produced more onions on slightly less land. Michigan’s 2,350 acres reflects its diverse agricultural economy but also highlights the lack of onion varieties developed specifically for its unique climate.

No varieties bred for Michigan

“They’re always changing, but there are no onions bred for Michigan,” said Bruce Klamer, an onion and celery grower near Byron Center and chairman of the Michigan Onion Committee. Growers organize observation trials to identify which varieties perform best under Michigan’s conditions.

This mirrors efforts across the U.S., where new varieties and seed hit the market each year. “The Michigan onion variety observation trials were started 15 plus years ago,” said Darryl Warncke, professor emeritus of soil fertility and plant nutrient management at Michigan State University. “The purpose was to observe how new onion varieties perform in comparison with the most commonly grown onion varieties at various locations in Michigan.”

Testing onion crop management strategies across the state

Each year, Michigan onion growers tour trial plots of new varieties before harvest. Klamer estimated as many as 60 varieties are grown across the state, most of them strong-flavored red or yellow long-day cooking onions that ripen in storage. A few growers experiment with sweet onion varieties, such as Expression from Johnny’s Selected Seeds.

“Developing an onion that has low pyruvic acid is a challenge for northern onions,” Klamer said. “A Michigan onion by itself — a cooking onion — has more sugar than a Vidalia does. But the pyruvic acid is a lot higher, and that’s what gives it the bold flavor.”

Warncke added that many good onion varieties are available for Michigan and other northern states, but growers keep evaluating new arrivals. He tested 17 varieties this year and 27 last year. Trials remain blind, with numbered rather than labeled entries. Five or six seed companies participate annually, each allowed up to five varieties at no cost.

Soil types and regional differences

To strengthen onion crop management strategies, growers test varieties in three locations: near Byron Center, Fremont and Grant. These sites reflect Michigan’s different soils and microclimates. Growers plant most onions in muck soils, but over the past decade some have shifted to sandy loam soils with irrigation. Holton-based Vogel Produce, which won the 2017 Master Farmer Award, perfected methods to grow both carrots and onions in Michigan mineral soil with irrigation.

Warncke noted that a few other growers now cultivate small acreages on mineral soils. “Early maturing varieties are harvested, cured and marketed in late July into early August,” he said. “Most of the onion varieties mature and are harvested in late August through September and put into storage. The onions are packed and marketed out of storage until the end of February.”

Community and collaboration

Klamer hosts a grower dinner each August to showcase trial results. The event includes steak, a short committee meeting and informal discussions. “Getting the growers out in August is important,” he said. “It’s kind of a nice meeting all the way around.”

Michigan onion growers strengthen their onion crop management strategies by continuing variety trials and sharing results. They adopt to soils, climates and market demands. Through these efforts, they ensure onions remain a staple of the state’s diverse agricultural economy.

— Stephen Kloosterman, associate editor