May 4, 2012Spring running hot and cold for fruit growers
States across the Midwest and East Coast experienced warmer-than-average temperatures in March. On average, temperatures were 15˚ F to 20˚ F warmer than normal for the month, said Tom Moore, coordinating meteorologist of Global Forecast Services at The Weather Channel.
Moore said that you’d have to go back to 1910 to find any record of a March similar to 2012. The biggest difference is that in 1910, it covered the entire country. This season’s warm spell only seemed to affect areas east of the Rocky Mountains, Moore said.
“This weather is really unprecedented,” he said. “It’s not only the percentage above normal we saw for each day; we broke records every day.”
So, what caused the unseasonable warmth? It was a mixture of things, Moore said, but the main reason was that the jet stream, normally in the southern part of North America about March, had moved into Canada. One of the causes of that was the lack of snow cover on the ground this past winter, he said.
“It’s not that there wasn’t snow, but there wasn’t sufficient snow cover,” Moore said. “The pattern to create snow wasn’t there, creating a lack of ice in northern latitudes.”
Snow was just one element in a chain of events that took place over the course of winter. Those events normally block the jet stream from advancing northward. That did not materialize this season, Moore said.
The early warm weather made growers in the northern regions more vulnerable to freezes. The “saving grace” for growers in the Great Lakes region could be the lakes themselves, however. Shoreline temperatures in the Great Lakes, and some larger inland lakes, above 40 degrees can offer protection.
“Just like with the air temperatures, having the water temperatures being that high at this time of year is unprecedented,” Moore said.
At the time, Moore warned that the Great Lakes states and others might return to normal seasonal temperatures, which is exactly what happened. That left growers scrambling to protect budding and flowering trees and plants as best they could.
The early warmth, followed by the cold snap, affected growers across the country.
“I think it is still too early to tell the extent of damage,” said Susan Brown, an apple breeder and horticulturist with Cornell University, in April. “I used to study peach and apricot damage and found that sometimes it took awhile for the damage to show – with early symptoms looking like water soaking and then turning dark.”
The main issue, Brown said, is that growers in New York state were three to four weeks early and were facing at least two months of potential low temperatures.
“I’m trying to remain optimistic,” she said.
It would take several weeks for farmers to determine the overall damage to the northwest Michigan tart cherry crop, said Phil Korson, president of the Cherry Marketing Institute.
As of mid-April, there were cold temperatures and some damage to cherry buds, more in tarts than sweets, said Nikki Rothwell, a district horticulturist at Michigan State University’s (MSU) Northwest Michigan Horticultural Research Station in Traverse City. She did not have a feel for how bad the damage was at the time.
Growers can survey for damage by collecting and dissecting flower buds, said Erin Lizotte, an Extension educator with MSU. For each 10-acre block, growers should cut and collect 30 branches representing the lower, middle and upper canopy, as well as from trees on the edges and interior of blocks, to get a good assessment of how the trees fared. If the block is located on a slope, make sure to collect samples from all elevations, she said.
Growers should open all the flower buds on each branch and inspect the pistils, which should be a vibrant, green color. If the pistil is black, the flower is dead and will not produce fruit. By keeping track of the number of buds checked and how many are dead, growers can get a percentage of viable buds in a block, Lizotte said.
According to the North Carolina Strawberry Association, this year’s strawberry harvest came as much as two weeks earlier than usual. Some farms were even earlier, with many starting to pick Easter weekend.
South Carolina strawberry growers were picking earlier than that. Berries normally hitting the market closer to Memorial Day were on sale in mid-April, according to the South Carolina Department of Agriculture.
Lisa L. Schacht, of Schacht Family Farm in Canal Winchester, Ohio, said Ohio growers with perennial crops were following the crops’ lead and hoping not to have issues later. Schacht is also president of the Ohio Producer Growers and Marketers Association.
“It’s mostly out of our control,” she said. “My vice president, Mike Hirsch, is a peach and nectarine grower. He said it would be better to have fruit developing rather than still in bloom if a cold snap hits. This will mean scarring is possible, but not total bloom loss.”
Schacht said her strawberry crop was ahead of schedule. But she, like growers in New York state, was approaching the planting of annuals like sweet corn and tomatoes on a typical schedule that would leave less of a chance of being caught by a damaging frost.
“The new concern is how uniform the state is in stage of spring,” Schacht said. “Producers from the Ohio River Valley area may not be that much advanced of the northern areas. We may see excesses in some crops and short seasons in others.”
Another concern is the nutrient uptake of the trees, said Amy Irish-Brown, an MSU Extension educator. Growers may have rushed into applying nitrogen early with the warm spell, but the trees may shut back down due to the April cold.
“Aside from freeze damage, we might end up with some small and weak fruit from lack of nutrients,” Irish-Brown said.
Another casualty of the low temperatures was southwest Michigan’s juice grapes. News reports said that as much as 10,000 acres of grapes were lost to a mid-April freeze, but Mark Longstroth, a small fruit Extension educator with MSU, said that assessment might be premature.
“We have to wait and see what was pollinated and made it through the spring,” he said. “We will know a lot more in a few weeks. Let’s wait a while before we walk away.”
* Reports continue to come in of crop survival and loss. Please share what you've seen on your farm.