PROSSER, Wash. -- A web-based grapevine cold hardiness tool has been launched for Washington grape growers by Washington State University researchers.

The site provides estimated low temperature thresholds for bud damage for more than 20 wine and juice grape varieties based on mathematical simulations of how grapevines respond to cold temperatures.

With AgWeatherNet stations across the state, the website enables growers to monitor temperatures in their vineyards in real time for potential damage. The thresholds programmed into the tool represent temperatures that would kill 10, 50 and 90 percent of a variety's primary buds.

If a threshold is reached a warning statement indicating the estimated level of damage appears on the website. The site also shows how well varieties are developing cold hardiness in response to local temperatures.

The tool was available online starting Dec. 1 at

Growers must be a registered users of AgWeatherNet to use the tool. Registration is free and online help is available on the page. A short how-to video is available on the WSU Viticulture and Enology Extension cold hardiness website at This site has information on preventing, assessing and responding to cold damage in vineyards.

-- Dan Wheat

Recommended for you