Effect of Cold on Grapes

LAKE ERIE VINEYARDS SHOWING EFFECTS OF WINTER COLD TEMPERATURES

-by Luke Haggerty, LERGP, Viticultural Extension Associate

PORTLAND, NEW YORK (April 21, 2015) -- Cornell Cooperative Extension Chautauqua County’s Lake Erie Regional Grape Program

As the season begins to change, and the landscape gets greener, we would like to forget about the recent harsh winter. For area grape growers, this is difficult as the past winter was particularly brutal for both man and grapevine.

February 2015 will go down as one of the coldest on record pushing many grape vines past their hardiness thresholds. On February 16th, early morning temperatures reached damaging levels for most regionally grown grape varieties. NEWA weather stations (http://newa.cornell.edu) recorded temperatures across the Lake Erie region from -17^ᵒF to -29.9^ᵒF. These winter lows left many grape growers concerned about freeze damage. In response, Lake Erie Regional Grape Program (LERGP) personnel combined efforts to determine the effects of the low temperatures on area vineyards.

LERGP analyzed over 15,000 grape buds to determine the scale of damage caused by freeze. As expected, tender vinifera wine grapes like ‘Riesling’ and ‘Cabernet Sauvignon’ received severe bud damage ranging from 70 to 95 percent. Hybrid wine grapes fared slightly better with bud mortality averages from 40 to 90 percent. However, these types of grapes only account for 4% of the 18,000 acres of grapes grown in Chautauqua County.

Most assessment efforts were concentrated on ‘Native’ varieties such as ‘Concord’ and ‘Niagara’ which make up 95% of the county’s grape production. Concord grapevines are relatively hardy compared to other grape varieties grown in the eastern US; a primary reason why the Concord industry has survived for so long in western NY. Freeze damage to Concord buds ranged from 20 to 80 percent. In a typical winter, Concord buds receive between 10 to 15 percent freeze damage.

There are multiple forms of freeze damage that can occur. Damage can develop in the buds, canes, or trunks. Bud damage will affect the current year’s production by killing the grape clusters forming in the buds. Trunk damage, however, can set production back three-to-five years as the vine essentially needs to regrow new trunks and the upper canopy which produces the fruit. Early assessment efforts were concentrated on bud damage and mortality as it is relatively easy to assess even when the vines are dormant. However, it is not until spring returns, and the sap is flowing in the vine, that trunk damage can be assessed.

Early assessment of trunk damage in Concord vineyards looks promising while assessment of the more tender wine grapes does not. The full extent of winter freeze damage will not be known until the early summer months when vines are in high demand for both water and nutrients. Injured trunks that cannot keep up with the demand may collapse and die at this time.

The February freeze event has made the 2015 season a critical time for LERGP and Cooperative Extension to assist the Lake Erie grape industry. LERGP will continue to provide sound, researched-based information to support all members of the grape industry in their efforts to deal with the effects of the brutal cold temperatures of the past winter.

The Lake Erie Regional Grape Program is a cooperative effort between Cornell and Penn State Universities; the participating Cornell Cooperative Extension Associations of Chautauqua, Erie, Niagara and Cattaraugus Counties in New York and Erie County in Pennsylvania; and participating industry partners National Grape Cooperative (Welch’s), Constellation Brands and Walkers Fruit Basket. The LERGP extension team provides research-based educational programming for commercial grape growers throughout the year at venues across the Lake Erie grape belt. For more information on LERGP, call 716-792-2800 or visit our website at http://lergp.cce.cornell.edu/

Photo Caption: Outer layer of bark cut away and corresponding cross section showing varying degree of freeze damage in grapevine trunks (Left) severe damage, (Middle) moderate damage, (Right) no damage. (Photo courtesy L. Haggerty)

The Lake Erie Regional Grape Program is one of many programs offered by Cornell Cooperative Extension of Chautauqua County (CCE-Chautauqua). CCE-Chautauqua is a community based educational organization, affiliated with Cornell University, Chautauqua County Government, the NYS SUNY system, and the federal government through the United States Department of Agriculture’s National Institute of Food and Agriculture. For more information, call 716-664-9502 or visit our website at www.cce.cornell.edu/chautauqua. Cornell University Cooperative Extension provides equal program and employment opportunities.

Last updated July 26, 2019