As of June 28, a high pressure system has settled on the entire West Coast, and weather experts are forecasting several days of high heat and possibly record-breaking temperatures. With that projection in mind, and with seeds beginning to harden and veraison on the near horizon, we decided to give the plants some water.
While we employ a technique known as deficit irrigation to control shoot growth and increase grape quality, we want to keep the plants alive. Over the next several days we’ll continue to feed the plants enough water to counterbalance evaporative losses.
These early-season high temps are preferable to those that occur late in the season, as the intense heat induces the green grapes to make sunscreen in the skins, which will provide protection throughout the summer.
When the heat recedes we’ll finish our cluster thinning pass, which we began several weeks ago. This involves culling excessive clusters and those on weak shoots with an aim to balance the fruit load to the age of the vine, its size, the size of the canopy, and the size of the shoots.