It’ hard to believe that it’s already August and more of summer is behind then ahead. If you look at the local vineyards it’s amazing how much the grapevines have grown in the last 4 weeks. The vines grow so much that we have to get into the vineyards now with work crews to perform what is called “Canopy Management”. Grapevine canopy management involves several operations designed to open the canopy and expose the fruit. The grapevine “canopy” is another word for all the leaves and shoots that make up the vine as we see it in the vineyard. Grapevine canopy management is another tool in our collection of Sustainable Practices. Sustainable practices are intelligent operations that reduce the need for pesticides and produce better fruit and wine (see my last blog on sustainable practices).
The first technique used in canopy management is shoot thinning. Shoot thinning reduces the shoot number per unit canopy length thereby reducing canopy density. In addition to reducing canopy density, thinning shoots also removes the clusters on those shoots. Excess crop reduces the aroma and flavor intensity in the wine. When a balance between leaf area and fruit is achieved the end result is a better glass of wine. Shoot thinning is actually done in mid to late June depending on the season and variety.
The second operation in Canopy Management is hedging the vines. This is done to remove any shoots that have overgrown the trellis and are hanging out in the row, shading the lower vine canopy. Once hedging is done the vine rows look like a formal hedge in an English garden with their beautiful recti-linear leaf canopies.
The last operation is leaf removal. In this operation a crew goes through the vineyard and pulls leaves that shade the grape clusters, exposing them to the sun. It may not seem like a big deal in the heat of summer but as the days grow shorter, the sun angle is lower each day and the nights are cool and long, the clusters need all the heat they can get to ripen. Think of a morning in early October when everything is damp with dew. Exposed clusters dry within minutes of the sun striking them. Clusters shaded beneath leaves may stay wet more than half the day. Wet, cool grapes are the perfect breeding ground for fungi that cause cluster rot. Removing leaves not only promotes fruit ripeness, it also reduces bunch rots by changing the cluster environment. As I mentioned in my last blog, Sustainable viticulture involves various enlightened practices, one of which is canopy management. By using the techniques of canopy management we reduce the disease pressure on fruit clusters thereby reducing the need for fungicidal sprays.
Doing the extra work to manage the vine canopies yields many benefits in terms of disease control and wine quality. Properly done, canopy management in summer makes for a better glass of wine at harvest and that my friends, is what it’s all about.
Dave Miller PhD White Pine Winery July 31, 2011
Dave Miller PhD
White Pine Winery
July 31, 2011