The warmth of the summer brings bloom and the grapevines are full tiny flowers that will soon turn into verdant grape clusters. Flowering normally occurs around the third week in June in the Willamette Valley, but can be later or earlier due to weather and other factors. We watch the weather reports a lot this time of year hoping for mild, dry weather without too much wind.
Once the flowers have been pollinated and fruit set determined, we turn our attention to crop yields. Grapevines that have produced an abundant number of clusters will never be able to ripen all of the fruit to the ripeness we are hoping for – too much of the vine energy is wasted by trying to nutritionally feed so many bunches at the same time. Alternatively, if we over-thin the crop, the vine will resort to using its energy to encourage vine growth and vigor – also to the disadvantage of the ripeness of the berries.
The vineyard crew generally makes two to three passes through the vineyard each summer, thinning the fruit in hopes of getting our yield to less than 2 pounds per plant. The first pass is made to thin each grapevine to one cluster per shoot. If we have 8-10 shoots per vine from our pruning and de-budding, we should have 8-10 clusters per vine before the grapes begin to ripen. To make quality Pinot Noir we need to thin the fruit, by hand, and selectively choose clusters to prune that are physiologically behind, poorly placed on the vine or have a poor set. This process is just one of the two dozen (or more!) times our vineyard crew will touch each grapevine by hand.. The second pass of cluster thinning generally occurs when the grapes begin to change color. This is called veraison, and it typically occurs in late July to mid-August. This second thinning helps to encourage ripening of the remaining clusters that are left on the vine without increasing the vine’s vigor..
Summer time is also canopy management time. With high-density plantings of 2,311 vines per acre (5,710 vines per hectare), the canopy needs to be managed carefully. We must prevent too much shade, while maximizing sun exposure and air flow. The goal is to manage vine vigor while exposing the vines to enough sunlight that they get optimal ripeness.
One way to do this is through trellising. Through a process called VSP (vertical shoot position), vines are trained to shoot vertically. Next shoots are secured in an upright position in between moveable wires that are adjusted through the growing season to capture the growing vines. Once trellised, it is easier to apply sprays, hedge the tips of the shoots, and pull leaves around the fruting wire.
Hedging is done mechanically to maximize precision, minimize excessive vegetative growth, and encourage the vine to focus its energy on the grapes. At the same time, leaves on the eastern or northern sides of the canopy are lifted to allow for optimal sun exposure.
Vineyard sprays, if used, are nearly entirely derived from natural products. To minimize powdery mildew (the biggest problem in the Willamette Valley) we spray each vineyard block roughly 6 to 8 times per growing season with mostly sulfur and some organic oils. The last sprays are applied two to three weeks before harvest.