Posted on Leave a comment

Under control: Using wind machines to battle winter frost

From the archives: Originally printed in 2010

Only about 40 per cent of farmers in the Okanagan and Similkameen valleys are using wind machines to help maximize their fruit production – and those who are, might not be using them as well as they could be.

“Of all of them, I would say that 30 to 40 per cent are using them properly,” said Don Cachola, former owner of Okanagan Wind Machines.

Cachola and his wife, Shana, installed and maintained the machines for 19 years, giving up the business in spring, 2008. Now, they are full-time orchardists, but still have strong opinions about the role wind machines play in fruit production.

“It’s only after someone puts one in, they realize what was lacking,” said Cachola. “A lot of people will say, ‘I have a crop, I don’t have damage.’” But it’s both quality and quantity that increases dramatically with the frost control measure.

For example, there are five apple blossoms in a cluster – and one of them is the largest. “That’s called the king blossom. But, it’s the first one to freeze,” he explained. That means even though, when harvest time rolls around, there might still be four apples from that cluster, the best of the lot may be long gone.

The first wind machine was installed in Canada in 1974, by Osoyoos’ William Dell. The technology has been used since the ‘20s in California, but was slower to catch on, further north. Now, they are a common sight, standing tall above orchards and vineyards.

“It’s basically a heater. It’s using natural warm air inversions to heat,” Cachola said. As things cool off overnight – especially on a clear night – heat begins to radiate off the ground and the trees.

“That heat rises up, and what ends up in place of it is cold air.” It can be as much as 5 or 9 degrees F warmer, just 50-feet up, where that warm air hangs out. “What the wind machine is doing, is pulling that warm air from above.”

The head of the wind machine is tilted, at about a six-degree angle. The blades force that warmer air back down, to keep the temperature of the trees just a little bit warmer. That few degrees can make all the difference.

Some consider the machines expensive to install, and expensive to run. The purchase price can be anywhere from $20,000 to $25,000 U.S., and they run on either gasoline or propane. The biggest ones – the ones that service about 10 acres of crop – can use as much as 12 U.S. gallons of gasoline per hour.

But there is no doubt in Cachola’s mind it is worth the expense. He said it can as much as double fruit production, and farmers more than make up for the outlay. “Oh, ya. A lot of times, in one season,” he said.

The wind machines are used in the spring, when trees start to come alive, to keep the emerging buds from freezing. But they can also be used by grape growers in the fall, to extend the growing season just a bit. That means more sugar in the grapes and a higher value. Some vineyards are now running the machines through the winter, to try to keep damage to a minimum. 

There are a few key points to remember, to get the most out of your machine. The first is kicking it up soon enough.

“A lot of people start them too late,” Cachola said. There are charts available, outlining the proper times to start wind machines, based on temperature and stage of tree (or vine) development. “Temperature is critical. It’s the actual temperature of the blossom themselves – not the air temperature.”

One of the ways temperature is lost is through radiation. That means by the time the heat transfers out of the blossom into the air, the blossom is already as much as 2 or 3 degrees F degrees colder. By then, damage is already done.

Cachola said one of the easiest ways to run the machines is to have an automatic sensor to turn the machine on and off. The alternative is a frost alarm, which wakes the farmer, who then heads outside and turns the machine on manually. But the automatic method saves more than just sleep – it also saves fuel on machines that run for more hours than they actually have to.

The other mistake people make is not keeping their machines properly maintained.

“All our late night calls were people who didn’t service their machines,” said Cachola. “You’ve made the investment – have the thing checked. People will have their cars services before a trip to Vancouver, but will let their wind machines sit for years.”

He recommends having the machine serviced in the spring or fall, by a professional. Frank Huschek, from Osoyoos’ Bowtie Tech Corp, agrees. He is the factory-authorized wind machine repair depot for Orchard Rite machines, and he said that he would recommend farmers get an hour meter.

“That tells them how many hours they’ve got on it,” he said, adding how often the machine needs servicing depends on how many hours it is used. His annual service checklist is extensive, and includes a change of engine oil, checks of coolant, battery, drive line, bearing, u-joint, gear boxes, air filters, and even the fan blades.

Leave a Reply

Your email address will not be published. Required fields are marked *