Published in Practical Winery & Vineyard
By Yun Zhang and Markus Keller, Washington State University

July 2013

Growers are constantly struggling to balance yield and quality in wine grapes. They are often asked to shut down irrigation sometime during ripening to achieve better quality. Moreover, a fear of dilution has led to the custom of not irrigating immediately pre-harvest.

Surprisingly, there is little scientific evidence to support this practice. For every economy-minded vineyard manager, the goal should be achieving the highest potential yield without compromising quality. At ripeness, 70% to 80% of grape berry fresh weight is water.1 Also, water as a solvent determines the concentrations of all important compounds (sugars, acids, phenolics, etc.) that are essential to fruit quality. Therefore, it would be difficult to overestimate the importance of berry water balance to the commercial yield and quality of grape berries.

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Irrigation // Viticulture //