A Washington State University study found that traditional spacings for juice grapes—around six feet between vines and nine feet between rows—was best of four vine density treatments in the trial. Dead and dying leaves, like these pictured, were commonly found in the three-feet vine spacing. Nutrient analysis showed that potassium from the dead leaves was being recycled back into the fruit and resulted in high pH juice in the three-feet spacing. Although high-density plantings have boosted profits in other fruit crops, a narrow spacing between Concord grape plants can reduce yields and returns, according to Washington State University viticulturist Dr. […]