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UC IPM Home > Homes, Gardens, Landscapes, and Turf > Fruits and Nuts > Environmental
Disorders
How to Manage Pests
Pests in Gardens and Landscapes
Fertilizing walnuts
Young trees benefit from light applications of nitrogen after one growing season has passed. If tree
shoot growth is limited, nitrogen may need to be applied. Keep the fertilizer at least 18 inches from
the trunk and water well after application. Divide the year's fertilizer amount into three or more applications
during spring, summer and fall. Water well after application. Fertilize as directed to avoid nutrient
deficiencies.
Fertilizer Rates for Walnuts
- For trees 1 to 2 years old an under
1-inch trunk diameter:
1 to 2 ounce actual N per tree=0.75 pound of ammonium sulfate
- For trees 2 to 5 years old with 1-
to 4-inch trunk diameter:
0.33 to 0.5 pound of actual N per tree = 1.75 to 2.5 pounds
of ammonium sulfate.
- For trees 6 to 7 years old with 4-
to 7-inch trunk diameter:
0.5 to 0.75 pounds of actual N per tree = 2.5 to 3.75
- For trees 8 to 10 years old with 7-
to 10-inch trunk diameter:
0.75 to 1.5 pounds of actual N per tree = 3.75 to 7.5 pounds
of ammonium sulfate
- For mature trees: 1.5 to 3 pounds of actual N
per tree = 7.5 to 15 pounds of ammonium sulfate.
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Healthy (left) and iron-deficient leaves |
Leaf deficient in zinc |
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