What works well on red wine grape varieties might be too much of a good thing for whites. Grape growers in Washington State have learned how to manage deficit irrigation on red varieties to produce high quality fruit, says Washington State University viticulturist Dr. Markus Keller. But he sees need for improvement on irrigation strategies for white varieties. Most growers tend to dry down the soils in white varieties too soon, said Keller. Moderate deficit irrigation is desirable for red wine grapes in most situations because it can help control canopy vigor, reduce berry size, and increase skin tannins and […]