It is the first of July and we are excited by the abundance and quality of the fruit we are seeing in the vineyard this year. The above average rainfall and later than normal spring rains have increased vine health and vigor while also increasing the number of clusters and the size of the canopy; Powdery mildew is an ever-present risk in our coastal climate, and the cool damp weather has forced us to work harder than normal at keeping our vineyards healthy.
Wet Spring
I am always amazed at the impact that natural rainfall has on the health and vitality of plants. Drip irrigation is an effective way to keep vines alive and productive, but rainfall fully nourishes the soil in a completely different way and vines respond. Buds burst forth in unison this year in a way that is very different from what we’ve seen over the last 4 seasons. It seemed like every square inch of vine pushed dormant buds. Primary buds have all pushed two clusters and on some varieties even the basal buds have pushed fruit (Syrah primarily). As a result we’ve got an abundance of fruit. In some varieties and sites we go through the vineyard and drop clusters of fruit to bring the vine into balance so we can ripen all the clusters to the level that we want in the wines.
Wine grapes are self-fertile and fertilization is negatively effected by dampness, cool weather, and wind. Most varieties did just fine this year, but the timing of Syrah flowering coincided with a really damp period and we saw a lower level of fertilization than in other varieties. This means fewer berries per cluster and looser clusters. All the other varieties we work with were unaffected and actually had very high fertilization.
Powdery mildew is the most common vineyard pathogen that we have to deal with in our climate. Humidty and temperatures between 75 and 85F are major drivers of rampant powdery mildew development. Every day in coastal Ventura County meets this criteria and we have to be extremely vigilant in our organic vineyard spraying, leaf removal, and canopy management programs. In addition, the smaller vineyards we work with often have large adjacent shade trees that prevent morning sun from drying dew in the canopy and contribute to pockets of mildew. Drier and hotter climates, like the high desert, don’t have to contend with this constant risk and don’t have to spray for mildew even once a season. In many years we utilize an organic spray program as many as eleven times per season to maintain control.We begin shortly after bud burst (early March) and continue until the grapes are fully through veraison (late July). There are synthetic fungicides that can reduce vineyard spraying to once per month, but we feel that their use doesn’t match our goals and we choose instead to use softer organic approaches. It is a big expense and takes a lot of time, but we feel like it is the right thing for us. The picture below shows an infected grape covered by powdery mildew.
