We are seeing veraison in the vineyard. Another vintage is on our doorstep. Veraison is the harbinger of harvest. When grapes start to change color and the hard berries begin to soften, you can bet on at least two things. One is that the earth's orbit around the sun is again approaching the harvest segment of our annual cycle. Another is that the grape berries have stopped growing and have begun the process of ripening. That is not all, however. Malic acid is degrading into tartaric acid. Acid is declining. Sugar content is going up. These are busy berry times.
I am always reminded of the fall color change in Northern Michigan during veraison. I hear that they have some fall colors in New England as well. Just as different trees develop their colors at different times, and for different reasons, the same is true with grape vines and individual berry clusters. Looking out over the vineyard one can see the patterns of different colors from vine to vine and from tops of hills to bottoms of swales. During veraison the individual grape clusters remind me of a cob of Indian corn with its variegated kernels of red and gold.
With veraison comes a change in vineyard irrigation as well. As we are properly reminded on an almost daily news cycle basis, we continue to experience a drought. David Girard Vineyards is fortunate in that it has access to El Dorado Irrigation District (EID) agricultural water which flows by pipe along Cold Springs Road. To be sure, we are doing our part through conservancy, careful monitoring, and otherwise marshaling limited water resources for efficient usage. We use only drip irrigation; we have limited our use of water for landscape purposes; and overall, we strictly limit our use of water except where necessary.
Over the growing season, mild water stress in the vineyard is not that significant. However, once veraison begins, too much water stress on the vines can be a problem. It can have an undesirable effect on ripening and vine quality. So once veraison begins, we are particularly vigilant as to the proper levels of irrigation required.
One consideration is our type of soil, which is decomposed granite, as in the Rhone Valley. Decomposed granite tends not to hold water. Another factor is canopy management. If the vines are cropped too heavily they will require more water. We also pay attention to areas of the vineyard with restricted rooting depth. Restricted rooting depth means less water holding capacity.
So what do we look for in the vineyard? We look for leaf scorch, leaf wilting, leaf loss, and suppressed growth. We also walk through the vineyard and feel how warm the leaves are. Warm leaves can indicate drought stress. To keep the leaf canopy balanced we go through the vineyard vine by vine and pull off leaves to achieve a canopy balance. We don't want the grapes to be burned by exposure to direct sunlight. But, we don't want all the plant energy to go to producing leaves either.
Veraison tells us another year is passing. It also tells us that we must continue to pay attention to what is going on in the vineyard by way of irrigation and canopy management as we approach harvest. Finally, it tells us that we had better start planning for the harvest.