CORRECTION: This article has been updated to correct information regarding the group responsible for grape hardiness testing and monitoring services for the Grape Growers of Ontario.
The unpredictability of extreme cold weather conditions in Ontario, such as the polar vortex that hit town this week, is creating new challenges for Niagara grape growers — from reduced icewine production to costly adaptations like wind machines, say some in NOTL’s grape growing industry.
The Niagara region has a unique microclimate that lets grape growers cultivate varieties of grapes that are more sensitive to the cold than others in vineyards elsewhere in the world.
It’s designated as prime agricultural land with restrictions on development, allowing grape growing to thrive, said Jamie Slingerland, director of viticulture at Pillitteri Estates Winery.
Niagara-on-the-Lake’s proximity to Lake Ontario and the Niagara Escarpment creates warmer conditions in town compared to inland areas of the region.
Growers select grape varieties based on how they tolerate the cold, market demand and the ability to grow a diverse portfolio of reds and whites for wineries.
More cold-hardy hybrid and vinifera grapes can be grown further from the lake, while the most sensitive varieties, like Merlot, should be grown closer to the lake, where temperatures are more moderate.
However, with climate change causing a rise in extreme weather events and conditions, growers aren’t getting the more consistent cold-weather temperatures they need to do their work properly.
“We’ve seen less opportunity to pick icewine,” he said.
Growers have adapted though, using more mechanized harvesting to quickly collect the limited icewine crop.
Grape buds gradually acclimate to colder temperatures and have better wind tolerance at the peak of the winter and have less tolerance at the start and end of the season.
Growers use large wind machines to draw warm air from above and mix it with the cold air near the ground, raising temperatures by 4 to 5 C.
“I’ve been using wind machines for about 15, 18 years,” said Coun. Erwin Wiens, who is also a grape grower.
“It makes all the difference,” he said.
But, maintaining and repairing the machines in cold conditions can be challenging.
“Some of them, for some reason, they just can’t get them started. Other times, a battery will die out unexpectedly,” said Slingerland.
Even though he makes sure to carry a booster cable and power pack with him, sometimes it’s not enough. Fortunately, he said, the winery does get help from the team at Lakeview Vineyard Equipment.
“They’ll have a crew in the middle of the night that’ll drive out to that machine,” said Slingerland.
This allows growers to monitor weather forecasts and get on-site temperature data to determine when to turn on their wind machines.
The low-temperature exotherm percentages indicate the temperatures at which 10 per cent, 50 per cent and 90 per cent of the buds would be damaged.
“Growers don’t just say: ‘Ah, I think I’m going to turn it on,’ because those machines are very expensive to operate, said Slingerland.
Since the machines require significant fuel and operating costs, growers still aim to activate them proactively — before temperatures drop too low.
Beyond what extreme cold weather means for growing and harvesting grapes, it also affects the traffic of visitors who come to NOTL’s wineries.
Nearly half of all wine sales occur at the retail stores inside wineries, which Slingerland said highlights the importance of the experience wineries provide.
Sure, there are countless Chardonnays worldwide.
But visitors are drawn to wineries for the unique experiences they offer, not just for the wine, he said.
“That’s why it’s such a delicate situation if something happens,” he said about extreme cold weather. “It really hits us.”
