MINNEAPOLIS (AP) -- On Wednesday Ross Nelson trudged outside at 3 in the morning to check the temperature in his apple orchard. He went back out at 6, and again at 7. And then he got a call.
A customer was worried about the cold weather's effect on Nelson's Apple Orchard in Webster, which gives apple-picking visitors wagon rides to its trees in the fall.
"Probably for the first time in the 37 years we've been in business, we will not be open (in the fall)," Nelson said he told the customer. "They thought it was terrible," he said.
Nelson has seen temperatures dip as low as 17 degrees on his 10 or 15 acres, where he grows 24 apple varieties. All over the state, a warm spring start has led to early apple buds now vulnerable to the recent cold. Nelson and other growers are concerned much of their crop will be killed off, leaving them without a paycheck and their customers without the crunchy Minnesota staple.
"I've never dealt with (this) in my life, my career," Nelson said.
Ralph Yates, secretary of the Minnesota Apple Growers Association, said that it will be several weeks before growers will know the extent of damage to the apple crop.
Apple growers with budding trees start sweating when thermometers sink to 28, said David Bedford, a research scientist and apple breeder at the University of Minnesota. At that temperature, trees can lose up to 10 percent of their buds. Just a tad lower at 25 degrees, he said, and they can lose 90 percent.
Usually, Bedford said, spring arrives late to Minnesota.
"The advantage of that over the years is that we're really not prone to spring frost," Bedford said. "What we've set ourselves up for is a little more vulnerability during the bloom time."
Yates, who is also manager of wholesaler Fruit Acres Inc. in La Crescent, said this year his trees "broke bud" on March 18, a full two weeks earlier than ever before.
Yates said some farms raise temperatures around the orchard with bonfires and others use wind machines to drive cold air out and warmer air down.
Bill Jacobson, who co-owns Jacobson's Pine Tree Apple Orchard in White Bear Lake, hired a helicopter at several hundred dollars an hour to do that for two nights this week.
"Did it work? It's too soon to tell," Jacobson said.
Nelson sprayed a simple potassium and sugar solution on his trees to lower the freezing point of his buds. But he's still not optimistic about the crop's survival.
"You get a paycheck every week. It's like your paycheck is taken away for that full year, plus you have to pay all your electric bills, all your pruning bills," said Nelson, who tends his orchard with his wife and three grown children. "Our family will not have any income for a year."
Minnesota Department of Agriculture spokesman Michael Schommer said crop insurance programs are available to apple growers in such situations. In cases of a weather disaster, the state can apply for federal aid on behalf of areas hit hard by devastation.
Despite potential hardships to growers, grocery store shoppers aren't likely to see a price bump in apples unless the supplies dwindle nationally, Bedford said.
While the state does a healthy business -- apples account for more money than all other fruit and nut crops at $12.2 million annually, according to the Department of Agriculture -- most Minnesota growers have smaller retail operations that sell directly to customers.
The three biggest apple producers, Washington, New York and Michigan, grow the fruit in huge volume and account for most of the distribution nationally. Bedford said there's no evidence yet of damage to crops in those states, though Michigan and New York have also experienced early budding and could be at risk.
Other crops are probably not as vulnerable, Schommer said. While apple trees are in the ground year-round, corn and soybeans that rake in $3 to $4 billion per year for the state are typically just now being planted.
Bedford and Yates both said there's leeway for apples growers to lose some blooms while keeping normal production.
"We only need about 15 percent of the flowers on an apple tree to become apples to have a full apple crop," Bedford said. But, he added, "Usually when we have these frosts, it tends to be more devastating."
Apples most threatened now are early-budding ones like Zestar, Bedford said. The state's most popular seller, the Honeycrisp, which Bedford helped to develop, is a mid-season bloomer and won't likely see as big a threat, he added.
For now, Yates said all growers can do is keeping warming their orchards while they wait out wintry weather.
"It makes the growers feel better, as if we're doing something," Yates said. "But in the end we're at the mercy of Mother Nature."
Copyright 2012 The Associated Press.