Every year in late winter or early spring, vineyard owners across the Northern Hemisphere prune back their grapes. This work is done by hand, and ideally while average temperatures remain below 35 degrees. At Carlos Creek Winery, we generally start pruning in early March, and with a crew of five, the process will take about month to complete. That’s a lot of cuts and a lot of labor! You might wonder, why is this necessary? There are three primary reasons we prune:
Vines only produce grapes on second year wood. So, if you never prune your grapes, they get wild and bushy with canes and leaves that won’t produce any fruit. This unchecked growth robs energy from the second-year canes that are trying to make grapes. It also makes finding and harvesting those grapes nearly impossible. So a big part of pruning is removing older canes.
Pruning vines allows us to selectively limit the number of second-year buds we leave on each plant. Controlling the number of grape clusters each plant produces is an important tool for vine health and grape quality. Given our short season, and each vine’s limited energy resources, limiting crop loads helps assure grapes reach maturity. Directing the vine’s resources towards fewer grapes also increases the quality of those grapes. Overburdening vines with heavy crop loads not only reduces quality, but it can weaken the vines and make them more susceptible to disease and winter kill.
The excess canes and leaves on an unpruned vine create an over dense “canopy” of growth, blocking sunlight and reducing airflow. This creates an ideal breeding ground for fungal diseases. Pruning allows us to control the vine’s growth and keep the canopy open. Exposing leaves and grapes to direct sunlight results in a healthier vine that requires less spraying and grapes that mature with higher sugar content and less herbaceous flavors. This pruning will continue throughout the summer as the vines continue to grow and leaf out.