Jim Willwerth takes samples of grape vines last winter for CCOVI's VineAlert program.

As snow and sub-zero weather blasted Ontario vineyards this week, Brock University was launching its cold hardiness monitoring program.

Operated by Brock’s Cool Climate Oenology and Viticulture Institute (CCOVI), the VineAlert program is now in its fifth year of helping growers in Ontario’s key grape producing regions protect sensitive varieties that are most at risk from frosty temperatures.

Over the dormant season from October to April, a grape bud’s ability to survive cold temperatures varies. VineAlert indicates at what temperature different varieties would see damage if a cold weather event occurred. This helps growers know when wind machines or other freeze avoidance methods are warranted to protect buds and vines from winter injury.

“VineAlert allows grape growers to be proactive when dealing with winter injury,” says CCOVI viticulturist Jim Willwerth. “It communicates important information about when preventive action may be needed.”

So far this fall, temperatures have already hit a low of -11.6 C. At that time however, VineAlert’s data shows that more sensitive cultivars such as Merlot and Sauvignon blanc were already cold hardy to -15.3 and -13.8 C, respectively.

If, over the course of the winter, the cold hardiness monitoring shows a potential damaging event, Willwerth and Kevin Ker, a CCOVI professional affiliate, first alert growers to the danger through the alert system. Then, after the event, they head to the vineyard to test grapevine bud survival.

“This bud survival knowledge is extremely valuable to grape growers,” Willwerth says. “If growers have not been able to prevent damage to the vines, winter injury can also be mitigated through pruning practices and adjustments in the vineyard that will allow for more consistent crops and reduce economic loss.”

Now with four years of monitoring results, the open data website is also drawing the interest of researchers and growers worldwide. Last year, the website’s data was viewed in 43 countries around the world and had more than 9,000 page views during the winter season.

Currently, VineAlert has more than 200 registered users receiving email alerts when cold events occur.

For more information, visit VineAlert online.