Spraying plants with dissolved aspirin boosts their immune system and health.
Contested
Aspirin spray isn't a proven plant tonic. There's a real kernel — salicylic acid does trigger a plant defence response in the lab — but home dosing is guesswork, results in the garden are inconsistent, and too strong a mix burns leaves. Lean on resistant varieties, airflow, clean tools, and pulling infected leaves; treat aspirin as a curiosity, not a routine.
What is actually known
There is a real phenomenon underneath this: salicylic acid — chemically close to the acetylsalicylic acid in aspirin — is a signalling molecule plants use to switch on systemic acquired resistance, a genuine defence response, and lab and greenhouse studies have primed that response with salicylates. But that is a long way from "dissolve an aspirin and spray." Home dosing is guesswork, garden-scale results are inconsistent, and too strong a solution burns foliage (spotting, scorch) — the opposite of health. It is not a substitute for the things that reliably prevent disease: resistant varieties, spacing and airflow, clean tools, and removing infected tissue. An interesting real mechanism, not a garden tonic to count on.
Evidence: not yet confirmed against its 2 sources.
what this rests on - 2 pointers
salicylic acid induces systemic acquired resistance in controlled studies
but garden-scale aspirin-spray results are inconsistent and overdose is phytotoxic; extension consensus
When would that grow at your place? →
Cite this page
Milpa Gardens. "Spraying plants with dissolved aspirin boosts their immune system and health." Evidence grade: Contested. https://milpa.garden/beliefs/aspirin-spray-aspirin-plants/
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.