Summer in the vineyard

Now that the school year has ended, and families have begun their vacation plans, vineyards are ramping up their summer season with a lengthy list of tasks that must be performed—now—in order to keep the vines healthy and ensure a robust harvest.

The vines are now producing vigorous growth, and this often requires canopy management to balance that vine growth with the healthy opportunity for ripening those grapes. Some vineyards will hedge or trim shoots and leaves to prevent overshading of the grape clusters, ensuring that the vines’ energy isn’t wasted on the canopy. For many vineyards, most of this hedging or leaf pulling is done by hand. Lest you think that this is easy, it’s not. The goal is to pull the less productive leaves, allowing for better ventilation of those bunches of grapes on the north or east side of the row. On the west or south side, it’s important to maintain adequate leaf cover to minimize sunburn on the grapes.

Suckers are another distraction for the vines, which take nutrition away without producing any grapes. This process, too, is carried out by hand. Much like we pull off stray shoots on our trees, we travel up ‘n down the rows, pulling off shoots that grow out from the vine, generally around the base. Known as suckers, these are removed in late spring, early summer, and often must be done twice during the season, depending upon how proliferate the vines are during the growth season.

Of course, there are weeds, always, and depending upon the type, they too can take nourishment away from the vines. Generally, we avoid chemical products and simply mow in between the rows. This allows the plant matter to decompose and return nutritional elements back into the soil. Weeds and grasses directly under the vines can draw moisture and nutrition away from the fruit, so they have to be removed. If left uncontrolled, these weeds and grasses can complicate harvest efforts. For those weeds and grasses next to the vines, they must be removed by hand, using a good old-fashioned hoe.

During the warm summer months, insects can likewise become a problem, especially sucking insects that can damage the grapes and/or carry infectious diseases to the vines, in some instances killing the entire vineyard. Most vineyard managers are out in the vineyard daily, checking vines and observing areas that could quickly become a site of infestation. A good viticulturist knows their vineyard and can easily tell you where problem areas are located and what they watch for throughout the season. This comes from walking the rows, checking the vines and becoming familiar with all aspects of their field.

And as temperatures soar, keeping those vines properly irrigated is critical to not only the harvest, but the long-term health of the vines. Most vineyards today are equipped with drip irrigation systems. This allows the precious water to only penetrate the soil next to the vine, minimizing evaporative loss, yet allowing the water to seep down directly to the roots. 

Fail to provide enough water to a thirsty vine, and the result will be unbalanced vine growth, reduced yield and poor fruit quality. Depending upon the varietal, the leaves may droop or curl, canopy growth will certainly slow, and in some varieties, the fruit may begin to shrivel. And when the temperatures hit 95 degrees or higher, the grapes tend to shut down, and go into survival mode. The vine effectively shuts down the grape’s photosynthesis, which causes the fruit to stop ripening. At this point, it becomes critical to keep those vines hydrated by watering.

Vineyard managers closely watch the temperature shifts during the summer months, anticipating upcoming hot spells, monitoring the health of the vines and checking on the ripening fruit. Temperature and light play a key role in fruit development. Once the grapes hit veraison [or the ripening phase], the grape berries will become softer, accumulate sugar, acids decline, and the color appears in red or purple fruit. Studies have shown that very high temperatures during the ripening phase reduce the key enzymes responsible for the coloration of fruit; thus, the need for those beautiful canopies—protecting those grape bunches during the summer heat.

So, while you’re out enjoying any number of great summer activities, there will be folks in and around Lodi toiling out among the vines—watching, protecting and ensuring that when it’s time for this year’s harvest, those grapes will be at their peak, and the vines will remain healthy for another year. Remember to raise a glass and thank those folks for helping to create that beautiful wine that you’re about to sip ‘n savor. Salute!