Cold temperatures returned this week after a mild spell, but neither was a lot of help for Iowa’s producers of some alternative agriculture crops. Jay Vermeer at Pella Nurseries has nearly forty acres of apple trees, and he says they took a hit from a spring frost two years ago. That year he figures they got 30 to 50-percent of a regular crop that year, "a lot better than nothing."
He says there’s no particular date when a late frost will hurt the most — rather, it depends on the development stage of the apple blossoms. He says the buds go from dormant to grey-tip, through stages called green-tip, half-inch green-tip, and then the tight-cluster stage, in which he’ll lose ten-percent of the blooming buds if the temperature falls below 28 degrees. Around 20-degree, the producers can expect a 90-to-100-percent loss.
Vermeer says he measured 18 degrees in one of his orchards this week, so some of the apples will be "long gone." "Our biggest problem isn’t that it’s so cold now," Vermeer says, "it’s that it was so warm earlier." He explains the recent weeks have been warmer than average, and that had the apple blossoms budding about two weeks ahead of schedule. "If we would have been where we were supposed to be, it could have got down to zero and it wouldn’t have hurt us at all." He says the nursery will have other fields and other varieties that aren’t a total loss, and will get by on sales of nursery stock and apple pies this year, without many fresh apples to sell.
"Chug" Wilson grows apples in Johnson County and says he lost his whole crop in the May freeze of 2005. "We didn’t make any money that year," Wilson says. But he says some did — the freeze destroyed the apple crop in central Iowa where his orchard is located, but growers got a crop in western, southern and northern Iowa, as well as Wisconsin.
Unlike orange growers in warmer climates, Wilson says apple growers have few options to try and save a crop from freezing. Overhead irrigation systems can spray water, which will give off heat as it freezes and keep the fruit right at 32-degrees…but nobody in Iowa uses those, he says.
Same for "smudge pots," and while he’s even heard of growers who hired helicopters to hover and blow warmer air over a freezing orchard, he says they spent a lot of money with "not much success at all." He and his wife Joyce run Wilson’s Orchard in Iowa City. The forecast for his region of the state calls for overnight lows at or below twenty degrees for three or four more nights before it warms up again.