Basil improves the flavour of adjacent tomatoes.
Contested
There's no evidence for this and no mechanism anyone has proposed. Plant basil next to tomatoes anyway — you'll want them at the same time in the kitchen.
What is actually known
No proposed mechanism. No trials. Extremely widely believed.
Evidence: none exists for the underlying claim - that absence is the point.
When would that grow at your place? →
Cite this page
Milpa Gardens. "Basil improves the flavour of adjacent tomatoes." Evidence grade: Contested. https://milpa.garden/beliefs/basil-tomato/
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.