Cold Hardiness Monitoring
This information is provided as a service by WSU with partial funding from the Washington Association of Wine Grape Growers through the Washington Wine Industry Foundation and the Washington State Concord Grape Research Council. Conditions in your area may vary depending on your specific environmental conditions and viticultural practices. WSU is not responsible for any damage from the use or misuse of this information.
Critical temperatures for wine and juice grapes are determined using differential thermal analysis as described by Mills et al. (1) and are updated weekly from mid October through mid April. The following information was taken from buds and canes (node positions 4-7) of mature vines grown at the WSU Irrigated Agriculture Research and Extension Center 5 miles north of Prosser and nearby commercial vineyards.
Clicking on a variety name will open the seasonal cold hardiness graph specific to the chosen variety.
|4/4/13||Chenin blanc||> +19||+12.0||+2.5|
Last updated by Lynn Mills on Apr 11, 2013 at 3:36 PM
BUD10 is the temperature (degrees Fahrenheit) at which 10% of the primary buds will be killed. Likewise BUD50 and BUD90 refer to 50% and 90% bud damage respectively. PHL10 refers to the temperature at which 10% of the phloem (bark) is damaged or when cane damage is starting. XYL10 is when phloem damage is complete and xylem (wood) damage is starting. This would be considered severe cane damage. Grapevines can survive more than 50% phloem damage and still be productive. When xylem becomes damaged, grapevine productivity and survival can be compromised.
Now that we are approaching bud break, we won’t be able to run exotherm analysis in grapes much longer. In previous years we have included the critical temperatures for several different varieties during the period leading up to bud break. Since every variety responds differently to cold, this should be used only as a rough guideline. In April of 1997 we ran some freezing tests on grape buds and canes at different phenological stages and found the following:
- Cabernet Sauvignon at first swell sustained no damage down to 25 F.
- Merlot at full swell showed slight damage to the buds, phloem, and xylem at 25 F. More serious damage to the phloem and xylem occurred at 23 F.
- Chardonnay at budbreak showed slight damage to the buds and phloem at 27 F. More serious phloem and xylem damage occurred at 25 F. Buds were seriously affected at 24 F.
- Interlaken at first leaf stage sustained cane damage at 28 F and leaf damage at 26 F. Both cane and leaf damage became serious at 25 F.
Cold hardiness values will vary in vineyards depending on preceding local environmental conditions. Temperatures during the 2-3 days prior to assessment of cold hardiness are particularly important. In general, if the temperatures in your vineyard have been colder than those at WSU-Prosser your grapevines would be hardier than the stated temperatures. Likewise, if the temperatures in your vineyard have been warmer than those at WSU-Prosser your grapevines would probably be less hardy. AgWeatherNet (the Washington Agricultural Weather Network) can be used to monitor temperatures at weather stations at over 130 locations in Washington. For more detailed information, the 2000 ASEV Cold Hardiness Workshop Proceedings (2) is an excellent resource on grape cold hardiness.
- Mills, L., J. Ferguson, and M. Keller. 2006. Cold-hardiness evaluation of grapevine buds and cane tissues. Am. J. Enol. Vitic. 57:194-200.
- Cold Hardiness Workshop. 2000. Proceedings of the ASEV 50th Anniversary Annual Meeting. Seattle, Washington. pp 35-114.
Cold Hardiness Model
A new model for predicting grapevine cold hardiness in multiple locations throughout the state is now available on AgWeatherNet. It provides the estimated critical low temperature thresholds for bud damage of over 20 wine and juice grape cultivars based on the locally observed temperature for each weather station.
Preventing Cold Damage in Grapes:
- Protecting Grapevines from Winter Injury - PNW #603E
- 2012 USDA Plant Hardiness Zones - The best way to prevent cold damage is to not plant in areas prone to it. Use this interactive map to determine if your area is at high risk.
Assessing Cold Damage in Grapes:
- Assessing and Managing Cold Damage in Washington Vineyards – WSU #EM042E
- Winter Freeze Damage and Vine Fruitfulness: Why does cold damage impact yield? – WSU Whitepaper
- Anatomy of Winter Injury – Cornell University
Responding to Cold Damage in Grapes:
- Effect of Pruning on Recovery and productivity of Cold-Injured Merlot Grapevines - AJEV 2007 58:351-357
- Vine and Vineyard Management Following Low Temperature Injury - ASEV 2000 Cold Hardiness Workshop