Chives or garlic planted under a fruit tree prevent apple scab.
Contested
There's no evidence that chives or garlic under an apple tree prevent scab, and no mechanism for it - scab lives in last year's fallen leaves and infects in wet spring weather. Choose a scab-resistant variety, rake up and bin the dropped leaves, and you've done the things that actually work.
What is actually known
A widely repeated permaculture-guild claim with no trial behind it and no proposed mechanism for how an allium's roots or scent would reach a leaf fungus. Apple scab (Venturia inaequalis) overwinters in fallen leaves and infects in wet spring weather; it is managed by resistant cultivars, raking up and removing the leaf litter, and where needed spray timing. An allium ring at the trunk does none of those things. It is the same shape as the garlic-deters-borers claim this corpus already records as having no evidence.
Evidence: none exists for the underlying claim - that absence is the point.
When would that grow at your place? →
Cite this page
Milpa Gardens. "Chives or garlic planted under a fruit tree prevent apple scab." Evidence grade: Contested. https://milpa.garden/beliefs/chives-garlic/
A garden-planning corpus: every claim states its evidence grade and links its sources on the page. Cite it with the grade, and add the date you read it.