{Juglans regia}

Boron Deficiency in Walnuts

If walnut plants are boron deficient, large, irregular, necrotic patches develop between the veins, particularly on the terminal leaflets. When boron deficiency is severe, the leaves are twisted and the veins are very prominent. Dieback from tips of the shoots results in very evident leafless branches. The nuts do not set properly and a marked reduction in yield can be expected. Walnut trees do not usually need boron supplemenation until they reach bearing age (12 years).

Photo courtesy of Dr. Patrick Brown, University of California-Davis

Soil Application (Suggested rates of application)

  Granubor Fertibor
LBS/ACRE 14-28 14-28
KG/HA 15.75 - 31.50 15.75 - 31.50

Foliar Application (Suggested rates of application)

LBS/ACRE 0.5-1
KG/HA 0.5625 - 1.125
Value in Use
Current Yield (Per Acre)
Expected Sale Price

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles. Learn more about Rio Tinto.

Copyright © 2024 Rio Tinto. All Rights Reserved.