Annual Life Cycle of the Grape Vine
As temperatures rise in early spring, sap begins to concentrate where the canes were pruned. Known as weeping, this is the precursor to all of the vine’s growth during the coming season. The ground temperature must be at least 50 degrees Fahrenheit for the process to start. This is the first step in the annual life cycle of the vine.
After the vine pools its energy, budbreak occurs. In California Wine Country, this usually happens sometime in April or early May. Budbreak is a vulnerable time in the annual life cycle of the vine. Spring frosts can be particularly damaging.
Early Grape Development & Flowering
During early grape development, sugars do not form, but the maximum yield is set. This usually occurs during late March or early April. The next step in the annual life cycle of the vine is Flowering, and usually occurs in May or early June. The small grapes are pollinated over a week or two and remain vulnerable to frost.
Next, the grapes begin their maturation process. Fruit set is when the grape flesh and skin tannins begin to develop. Unfortunately, this does not always occur evenly within clusters. Fruit that does not properly develop is pruned.
Sometime in August, the grapes finally begin to change color. This is the next step in the annual life cycle of the vine, and is known as veraison. This is a critical time in the vineyard’s life cycle. During veraison, the vineyard workers prune the canopy and excess grape clusters. At this stage, the grapes still taste sour and are immature.
Tradition dictates that harvest will occur 100 days after flowering, but this decision is ultimately the vineyard manager’s. A date is selected based on the varietal as well as sugar and acid levels. Testing for the latter two variables is frequent in the final weeks and days. This represents the end of the annual life cycle of the vine.
After the vineyard manager accounts for all of the variables and decides that the time is right, harvest begins and the life cycle of the vine starts over again.
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