The Annual Life Cycle of California Vineyards

The annual life cycle of California Vineyards is generally considered to begin in the Fall immediately after the previous years harvest. During this time, vines lose their leaves and begin to go dormant.

The vineyard managers primary concerns are pruning the vines and ensuring that they are protected from cold temperatures. Nature helps with the second objective.

Sap from the vine drips towards the roots and creates a natural layer of insulation. Dirt can also be mounded around the roots for added protection.

Depending on the severity of the climate, vineyards are normally pruned sometime within three months after harvest. In very cold climates pruning is delayed to the end of this time frame.

The longer pruning is put off, the later budbreak will occur in the Spring. In colder climates it is beneficial to postpone budbreak so the vine is not adversely affected by a late cold streak.

There are three major pruning techniques: cordon-spur pruning, head-spur pruning and cane pruning.

Cane-pruning usually involves cutting off all but three or four canes. Canes are selected based on the number of buds they produce.

Head-spur pruning is widely used in the Rhone Valley in Southern France and is also popular in warmer wine producing areas in California. This method effectively keeps grapes near the ground and allows them to continue to ripen at night due to the heat retention of the soil. It is generally not used in cooler climates because it can expose grapes to frost-bite.

Cordon-spur pruning is head-spur pruning but with a trellise system in place to train a few canes with a specific number of buds away from the earth. This method of pruning is the most conducive for machine harvesting.

As temperatures rise, canes begin to grow and budbreak approaches. In California, this usually occurs in April or May. This may be the most hazardous time of the vineyard cycle, as remnants of Winter weather can hurt vines during this vulnerable stage. Flowers begin to form in June.

Grapes begin to develop and by mid-August, the vineyard reaches a time called veraison. This is the time when some grapes begin their color change and is another critical time in the vineyard life cycle. During veraison, the vineyard manager may prune leaves as well as some grape bunches. At this stage, the sugars are undeveloped and grapes still taste sour.

Although tradition dictates that harvest will occur 100 days after flowering, the decision to begin is ultimately the vineyard managers. 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.

The weather can dramatically affect grapes at this stage either positively or negatively. Late rains can dillute sugar levels and excessively high temperatures can detrimentally lower acidity. This can make wines either flat and boring or overly alcoholic. The risks of leaving grapes on the vine for too long must be weighed against the need to develop varietal characteristics.

After the vineyard manager accounts for all of the variables and decides that the time is right, harvest begins and the cycle starts over again.