How to Manage Pests

Pests in Gardens and Landscapes

Harvesting and storing walnuts

It is important to harvest at the earliest possible date to avoid worm damage to nuts while they are still on the tree and to minimize damage from rains. Begin to knock the nuts out of the trees as soon as the hulls begin to split and pick them up as soon after harvest as possible.

After harvest, the nuts should be hulled and prepared for storage. Once hulled, rinse the shells with water to remove the surface tannins that may stain the shell. Spread the hulled nuts out to complete the drying of the kernel inside. To determine if the kernels are dry enough for storing, shell and try to break the kernel in half. If the kernel snaps cleanly rather than bending, the nuts are ready. For best long-term storage, freeze hulled nuts for 48 hours and then seal in airtight containers or plastic bags. This will kill any insect pests and their eggs and prevent loss during storage. Nuts still in the shell may be stored for many months in a cool dry place. Shelled nuts will keep for several months if refrigerated or frozen.

Harvest once the husks split
Harvest once the husks split

Statewide IPM Program, Agriculture and Natural Resources, University of California
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