Cold damage to grapevines continues to threaten Washington’s grape growers. As the record low temperatures in early October demonstrate, growers can never be sure when a cold event will occur nor how severe it will be.
This is why the WSU viticulture research team, led by Markus Keller, continues to collect data from buds and wood pieces from a range of grape varieties in order to determine “critical” temperatures (the temperatures at which the tissues freeze and are killed) for each variety.
Because the temperature at which the buds and canes freeze depends on the variety and fluctuates throughout the winter, such information is important to growers needing to make frost-protection decisions.
The latest cold-hardiness data are posted each week on WSU’s wine science website (https://bit.ly/3j0Ces) from early October through April.
In addition to Washington’s “standard” varieties, the WSU team also evaluates emerging varieties of interest to the industry.
Website visitors may click on a variety name, which will open a new window with the seasonal hardiness graph for that variety along with the temperature profile. Growers may use these graphs to follow seasonal trends and forecast approximate hardiness levels based on current temperatures at their site.
The service is funded by WSU, the Washington Association of Wine Grape Growers through the Washington Wine Industry Foundation and the Washington State Concord Grape Research Council.
