Deep freeze could damage grape buds

John Christensen
With winter stretching out for eight more weeks, vineyardists are keeping an eye on how their vines are holding up to the deep bitter cold of 2014.

The recent bitter cold temperatures brought by the headline "Polar Vortex" and the "Bombogenesis" storms are of great interest to those trying to keep up with heating bills, but may have an even deeper impact on the local economy. Vineyardists and winemakers are watching when the temperatures plummet and dreading what it could already mean for their harvest and the 2014 vintage.

Glenora Wine Cellars owner Gene Pierce writes in his latest "Glenora Gazette" blog of what he has seen of the damage so far. "At this point is fair to say that there has been bud damage, however the significance of the same is not a 'cold' hard fact at this time," he says with a hint of good humor.

Pierce receives reports from Network for Environment and Weather Applications (NEWA) stations set up in vineyard locations throughout the Finger Lakes Wine and in other fruit growing regions that showed the coldest temperatures were Wednesday morning, Jan. 22. The coldest temperatures were recorded at the northern part of Seneca and Cayuga Lakes at Geneva with -13.9 degrees and Varick with -11.5 degrees. Farther south, Dresden had -6.7 degrees, Glenora had -5.8 degrees, and the warmest, "if it could be called that," says Pierce, was at the southern end of Seneca Lake at -3.6 degrees. "Everyone, or at least those who are paying attention, is collecting canes/buds for analysis," adds Pierce.

Those paying attention include Louis and Donna Gridley whose vineyards are at the crest of Bluff Point above Keuka Lake, a considerably higher elevation. "It varies a lot from farm to farm and by variety," says Lou, who recorded a sustained -6 degrees in Jerusalem last week. Of the buds he and Donna have collected, they have 20 percent bud mortality in Concords, 29 percent in their Cayuga/Riesling hybrids, and a frightening 53 percent in Rieslings. Donna adds that the strain on the vines from last years' bumper crop may also be contributing to the bud mortality.

Cornell Cooperative Extension of Yates County Vineyard Specialist Hans Walter-Petersen agrees. With some spots recording as much as 10 to 12 degrees below zero, there could be significant impacts on the next harvest, but even the experts won't know the real impact until spring. "Viniferas like Chardonnay, Gewürztraminer, and Merlot are generally hit the hardest," he says, adding that French hybrids are more cold tolerant, and natives like Concord, Catawba, and Niagra are hardier still. Where he has tested near Hector on Seneca, he is seeing about 20 to 25 percent bud death among viniferas, and 5 to 6 percent in natives. In spots, he has seen 30 to 40 percent loss in Riesling, echoing the Gridley's observation. "We're still much better off than Indiana and Ohio," he adds after seeing the almost total destruction of buds during a recent visit.

Walter-Petersen describes the survival mechanism vines possess against such damage. There are three levels of buds: primary, which will bear the most fruit, but are the least cold hardy; secondary, which will have less fruit but are hardier; and tertiary, which rarely bear any fruit, but are the hardiest and whose leaves will insure the vine's survival.

Yet it is not only the intensity of the cold that can be a problem. Pierce says, "Temperatures were close to 50 degrees Jan. 11. Therefore, in some cases there has been a 60-degree plus temperature change in a 10 day period. That can be more dangerous than the cold temperatures." Walter-Petersen concurs, adding that wide swings in temperature can even cause trunk damage and vine death.

That is an issue the Frank family solved years ago. High on the hills of Pulteney southeast of Keuka Lake, Dr. Konstantin Frank pioneered the practice of hilling a foot of earth around the base of his vinifera vines with a special plow after the harvest is finished in the fall. "That earth," explains grandson Fred Frank, "plus any snow fall, covers and protects the graft union (where the vinifera vine is connected to the native root stock) and the basal buds." The earth must be pulled clear of the vines in the spring using a take-out plow, but Frank explains that this acts as a cultivator and reduces their need to use herbicides. Hilling has allowed Dr. Frank's Vinifera Wine Cellars to maintain some of the oldest vineyards in the country in a place Dr. Frank had been told his vines could never grow because of cold winters like these.

"There is a lot of uncertainty right now," says Fred. "The damage is cumulative, and we'll do a more thorough check at the end of February. But last year's bumper crop and good quality crop means that most wineries have pretty high inventories. That lessens the blow and helps us weather any damage like this year could see."