Black Walnut Toxicity Killing Garden Plants: Juglone and Solutions

The Problem

Black walnut roots exude juglone — toxic to tomatoes, peppers, eggplant, potatoes, and many others. Effective radius: 40–80 ft from trunk.

Options

1. Move garden outside root zone.
2. Remove tree — juglone persists 2–3 years after removal.
3. Containers with clean soil (isolated from ground).

Soil Remediation (If Staying)

• Solarize (black plastic 6–8 weeks).
• Amend heavily with organic matter.
• But juglone is extremely persistent — success unlikely.

Resource

OSU Extension: Black Walnut Toxicity