The killing temperature of Vinifera, Pinot Noir, Pinot Gris, Chardonnay etc...is -23 degrees Celsius. Hybrids such as Baco Noir are hardier than Vinifera. Although the killing temperature is -23 for Pinot Noir, damage starts to occur at -12 or even warmer if there is damage from mildew or other diseases. This damage can limit next years crop, by killing or injuring the Primary buds on the cane. Baco Noir and Vidal are hardy to about minus 27. While Marechel Foch is hardy to -30, Minnesota hybrids, such as Frontenac and Frontenac Gris, which were bred by the University of Minnesota are hardy, to about -40.
To avoid the damage caused by the winter cold, here in the County we bury some of the canes. Essentially with Vinifera we bury or lay down 1 or 2 canes each way from the vine. These canes are then "hilled up". Hilling up is completed after harvest, obviously, and before the ground freezes. Basically the same you do to roses to protect them from the cold, but on a much larger scale. This is done with a grape hoe on the side of the tractor and a vplow off the back of the tractor. The higher the hill, the more dirt on the canes, therefore the more protection on the canes. This dirt then needs to come off in the spring which we will cover when its warmer.
So now lets sit back by the fire and enjoy a glass of County Pinot.
