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- Slimmer Pickings
Research shows fewer harvests better for asparagus
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By Karen Gentry
Associate Editor
After nearly 10 years of asparagus research 22-24 pickings or harvests was determined to be optimal for yield and spear size of hybrid asparagus.
John Bakker, manager of the Michigan Asparagus Industry Research farm in Hart, Mich. supervised research plots to test different amounts of asparagus harvests. The plots tested 15-16 pickings, 22-23 pickings and 28-29 pickings. Every second year the spears were sorted into size categories based on spear diameter.
The ninth full season was in 2000 after the initial planting in 1989. Research efforts helped to determine the optimum amount of yield from a field without doing long-term damage to the field, according to Bakker.
“By the third or fourth yield there was already more yield on the 22 (pickings) than the 28 (pickings). It appears the 22-harvest season is about right,” Bakker said. For 22-25 pickings the harvest is normally six weeks beginning around May 1, according to Bakker. The 15 picking season is obviously a shorter harvest season, he said.
Research plots were harvested in 1992 through 1999. “I was a little bit surprised about how quickly the 28 harvests per year hurt that plant,” said Bakker. He said by 1994 the amount harvested in the 28-29 pickings was only slightly more than the 22-23 harvests. By 1995 there was more yield off the 22-23 harvests than the 28-29 harvests and that continued every year after, he said.
Bakker said it was also surprising that although there was more yield off the 22-23 pickings compared with 15-16 pickings, it wasn’t as much as expected. Averaging nine years of harvest the 15-16 pickings yielded 3,076 lbs./A, the 22-23 pickings 3,745 lbs./A and the 28-29 pickings 3,545 lbs./A.
Changing market
Growers are facing a rise in asparagus imports and a supply that is starting to slightly exceed demand. The question facing growers is the viability of going to 15 pickings to control the price or to continue with 22-24 pickings for optimal yield that may contribute to oversupply.
Barb Dartt, from Michigan State University’s Department of Agriculture Economics, spoke about the economics of different numbers of pickings, at the recent Asparagus Day in Shelby, Mich. on March 8. She posed the question to growers, “Is a short season at a higher price better than a long season at a lower price?’
A worksheet she developed takes in many factors such as that the long season would typically generate 3,000 pounds per acre and the short season 2,400 pounds per acre. Growers need to consider three main cost changes when switching from a long to a short harvest season. For a short season additional chemical applications are needed and there are fewer trips across the field needed. The third cost difference is the decreased harvest expense with a shorter season.
Through the worksheet growers can calculate a breakeven price needed in a short season to generate profit equal to a long season. The worksheet will be available in mid-March at www.aec.msu.edu/agecon/faculty/index.htm.
“With 1-3% oversupply prices can quickly go into the toilet,” said Bakker. The question for growers is to limit supply and only harvest in a four- or five-week season or harvest the full six-week season for optimal harvest to get maximum yield.
Growing for the fresh asparagus markets presents a dilemma for growers. “The fresh market prices fluctuate pretty widely,” said Bakker. Early in the season in May prices are low because the states of California, Washington and Michigan are all in the market at the same time. By mid-June and later the prices come up quite sharply, according to Bakker.
As the prices go up, growers are typically past their 22-23 pickings, although the research has shown that 28-29 pickings can cause damage to the fields.
Over 80% of asparagus in Michigan is grown for processing with processing prices bargained for and set in March. Jerry Campbell, manager of the Michigan Asparagus Growers Division of MACMA, said a committee of asparagus growers typically makes a price recommendation after March 15 in anticipation of the marketing season that begins April 15.
There were 410 asparagus growers in Michigan in 1998-1999, with a heavy concentration in Michigan’s West-Central region, according to the Michigan Agricultural Statistics Service. Asparagus was grown on 16,500 acres in Michigan last year.
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