Wind machines are one option growers in the Niagara region of Ontario, Canada, are pursuing as they seek to protect their vines against future bouts of cold weather.

Last winter, cold weather in January and February killed most of the buds on the vinifera varieties. The damage reduced Ontario’s total wine grape crop to just over 18,000 metric tons-about half what it should have been.

The 2005 crop was even smaller than in 2003, when winter damage reduced the Ontario grape harvest to around 26,000 metric tons. Between 2004 and 2005, the value of the wine grape crop fell from Can.$45.5 million to $19.6 million. Many vinifera growers saw losses of 90 to 100 percent, said Ray Duc, owner of Forrer Farms, Ltd., in Niagara on the Lake.

The shortage was critical enough that wineries secured permission to cellar wines with up to 99 percent foreign juice. Though quality-assured Vintners’ Quality Alliance wines must use only Ontario grapes, the short-term flexibility on foreign content allows wineries to make the most of what little supply they have.

Pinot Gris, Sauvignon Blanc, Cabernet Sauvignon, and Merlot were the vinifera varieties hit hardest by the cold weather. Hybrid varieties survived better.

Vidal, the primary variety used for Ontario ice wines, as well as the red varieties Baco Noir and Marechal Foch, fared particularly well. Fortunately for growers, all three make decent varietal wines as well as rounding out blends.

"But they’re not what you need to build an industry on," said Duc, whose 200-acre vineyard has 13 types of grapes. The primary varieties are Chardonnay, Riesling, Cabernet Franc, and Merlot. "We need to get these vinifera through the winter."

The Grape Growers of Ontario, an industry organization that Duc chairs, has contributed to a $250,000, three-year study of wind machines and their effectiveness in protecting vines. The study also is funded by growers, other industry groups, and the Ontario government.

Dr. Helen Fisher, an associate professor in the Department of Plant Agriculture at the University of Guelph, is one of the researchers involved with the study. While growers have become more skilled in preparing vines for winter, she believes wind machines will help reduce the risk of winter damage.

"It’s one way to minimize the problem, but it’s not going to make the problem go away," Fisher said.

Wind machines promise to reverse the temperature inversions considered responsible for colder vineyard temperatures. During inversions, air 40 feet above a vineyard can be as much as 10 degrees warmer than air at ground level.

Wind machines push warmer air above a vineyard downwards, raising ground temperatures by as much as three to four degrees Centigrade. The increase is just enough to prevent vineyard temperatures sinking below the critical -20°C mark (-4°F) that virtually guarantees winter damage in Ontario vineyards.

Though typical winter temperatures in January and February don’t usually go much lower than -8°C (18°F), the extreme minimum for the Niagara area is -25°C (-13°F). The 2005-2006 winter saw a warm January, but trials of the fans in vineyards around the Niagara region, including Duc’s vineyard, indicated that they had helped reduce winter damage to vines that might have awakened during the warm weather.

Duc said growers can set the machines to come on at different temperatures. Since the dormancy of vines means they aren’t always at risk from severe cold, Duc said it’s important that growers have control over the fans.

A deep, consistent cold ensures the vines stay dormant, for example, reducing their susceptibility to cold weather. Warmer weather, which the Niagara region saw this past January, could disturb the vines’ dormancy, making them more susceptible to a sudden cold snap. As a result, growers set their fans to activate at a slightly higher temperature than usual in January.

"We’re not really basing that on any science, just grower knowledge," Duc said, underlining the need for the study to determine how best to use the wind machines. "Hopefully, it works."


Duc, who has spent nearly $500,000 on 15 wind machines for his acreage, is not the only grower who believes the technology can help. He estimates that Ontario growers have spent upwards of $10 million on wind machines to protect their vines against winter damage.

Duc said the machines are expensive to run, but the cost is a small price to pay for protection of the crop, especially if the machines are run efficiently. The current study will yield tips, he said.

"We need to know when to turn them on without going broke," Duc said.

Grape growers and winemakers aren’t the only ones hoping the machines provide an antidote to cold snaps and that crop volumes recover.

The wine industry in Ontario has suffered from crop failures as well as a decline in tourist volumes in recent years, partly because of security concerns as well as the occurrence of Severe Acute Respiratory Syndrome (SARS) in Toronto.

Together, they have made for grim times for suppliers to the wine industry such as Jim Hedges, who launched a line of barrels made from Canadian oak in 2002. The short crops and lack of tourist traffic has stymied Hedges’s initial plan to market and establish his barrels in the Niagara region before going after any international business.

Several wineries were drawn to Hedges’ unique barrels following their launch in 2002, but the short crops have meant many wineries have been limited in their ability to invest in new products.

"Our best customers just didn’t have things to put in barrels," Hedges said. "For us, the last three years have hit at a very poor period. If it had been the late nineties, we’d probably be just booming by now because everyone had lots of juice."