With winter rainfall averages well below normal for the state, many grape growers are experiencing significant challenges with moisture deficient soil profiles.
“On the North Coast, we deal with these dry season starts very infrequently,” says Dana Grande, viticulturalist with Jordan Vineyard and Winery in Healdsburg. “It becomes a tough task to balance the need for a healthy plant for optimum fruit set with the early season stress/slow-down for wine quality. We have begun irrigation in blocks where soil moisture probes show significant dryness in the soil.”
If there is a silver lining to the situation, Grande says it might be in assessing nutrient levels. “I would think that my bloom time petiole results will be more accurately reflecting the nutrient levels in the plant,” she says. “So many times with wet, cool springs, both macro and micro nutrients are depressed in the analyses due to the inability of the plant to pick up these nutrients from colder, wetter soils. We'll see if that is true. They look good so far, and I haven't seen phosphorus levels this high in many years!”
A relatively mild start to the season has yielded very little pest pressure and only a mild concern over disease pressure to date. “There has been nothing significant so far in terms of pest pressure,” Grande says. “I do have some patchy Willamette spider mite populations in some blocks. It’s nothing significant enough to warrant treatment at this point, but enough of a population that I have changed my mildew program to a Stylet oil program - off of the sulfur - to help to suppress the overall population. With all of this nice weather favoring high powdery mildew pressure, we have tightened up the intervals on our prevention materials.”