The bloom is off the vines now, heralding the beginning of fruit set. Fruit set is when the flowers develop into berries, which grow and ripen over the summer. Around 30-50% of the flowers develop into berries, this number being influenced by environmental factors along with the vine varietal. Optimal environmental conditions for flowering and fruit set are strong light intensity (which we’ve had in abundance this year), warm temperatures (also present), adequate soil moisture (not so much) and nutrient availability. As I mentioned a couple of blogs back, we did some shoot thinning earlier to maximize light penetration. To combat the serious lack of rainfall, we started irrigating early during bloom to ensure adequate soil moisture.
We’ve been blessed with favorable, albeit dry growing conditions this year and thus we hope to have virtually no- viticulture term of the day alert- “shatter” which is poor fruit set, where the flowers don’t develop into fruit. Unfavorable conditions would be rain (certainly not a problem this year), wind, cold weather or an over or under supply of nutrients. All of these lead to an increased incidence of shatter- or colure if you want to add to your French vocabulary.
As we get into fruit set, the vines go through another shoot thinning to maximize sunlight exposure and to provide good airflow to combat mildew. The next stop is veraison, a topic in the near future, the time when the berries stop growing in diameter, turn color, and begin to soften- and the countdown to harvest begins.