Life Cycle of the Vine
As weather warms (April in Oregon), carbohydrate stores begin to move up from the deep roots into the vine. The small nodes on the canes begin to swell, eventually pushing through new baby leaf growth signaling the start of the growing season.
These nodes formed during last year’s growing season are waiting for their day in the sun. At this stage, they are extremely delicate and vulnerable to damage from strong rains or hail.
The tiny caps that have formed on the clusters begin to fall off revealing tiny flowers. The grape cluster is at its most vulnerable during this stage. Wind, hail, rain and frost can irreparably damage the fruit set. This stage can last one to three weeks, depending on the weather. Grapevines are self-pollinating with the help of wind and tiny insects. With optimal weather conditions, all of these flowers will begin to grow as pollinated grapes.
Color begins to show during veraison. Red varieties deepen and begin to turn red, black, gray, or blue, while green grapes soften and start to show more golden colors. Berries double in size and malic acid reduces. Sugars (glucose and fructose) begin to migrate from the leaves into the berries.