Better water management creates more desirable walnuts

Close attention to water management can help prevent undesirable walnut characteristics like a darker pellicle colour, shrivel, thin shell, and peewee nuts.

Bruce Lampinen, walnut and almond specialist at the University of California -Davis- told growers at the 49th annual Tri-County Walnut Day that optimum water management just prior to harvest will help them avoid pellicle colour issues.

Other factors that can affect walnut quality were mentioned, including leaf loss due to shading, disease or water stress, sunburn, hull damage by husk fly, disease, high temperatures during harvest, and soggy orchard floor conditions at harvest.

According to an article on, colour problems in the 2017 walnut harvest, were the result of very high summer temperatures and irrigation issues. Sunburn was worse on trees in very wet soil conditions. There is not yet a clear connection between temperatures and pellicle issues when irrigation issues are also involved.

Publication date: 3/2/2018

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