Dormant Zinc Sulfate on Apples: Wrong Tool, Wrong Time

Grower asks if dormant zinc sulfate benefits apple orchard.

Why It's Ineffective

• Zinc sulfate = fungicide (primarily)
• Dormant trees have no leaves—fungal targets absent
• Trunk moss/lichen: minor benefit only
• No insect control
• Waste of material, labor, time

Correct Dormant Strategies

• Dormant oil: For scale, mite/aphid eggs (if history of problems)
• Copper spray: Fire blight prevention (timing critical—before green tip, avoid russeting)
• Sanitation: Remove mummies, cankers, fallen fruit
• Pruning: Open canopy for air/light

Zinc's Real Role

Zinc deficiency = "little leaf," rosette, blind wood. Correct with:

• Chelated zinc foliar at silver tip/green tip
• Soil zinc if deficient (test first)

Read labels. Dormant zinc sulfate = no ROI.