What is the best way for Washington State grape growers to analyze nitrogen levels in their vineyard? Washington State University soil scientist Dr. Joan Davenport believes that growers will get more out of a spring soil test than spring tissue analysis when trying to measure the nitrogen status of their vineyards. “I definitely walk a very different path about leaf tissue testing and sampling than the guidelines that come from California,” she said, noting that California vineyardists typically take petiole samples at bloom. “In Washington, we’d be better off taking a spring soil test to find out what we have […]