Sprinkling baking soda around tomato plants makes the fruit sweeter.
Refuted
Baking soda won't sweeten your tomatoes. Sweetness is sugar the plant makes in its leaves from sunlight, not something soil pH controls — and baking soda's sodium actually harms soil and roots. For sweeter fruit: a sweet cultivar, full sun, healthy leaves, and letting it ripen on the plant.
What is actually known
How sweet or tart a tomato tastes is set by the sugars and acids the plant makes in its leaves and loads into the fruit — driven by the cultivar, by sunlight and healthy foliage, and by ripening fully on the plant. Soil pH does not titrate the fruit's acidity, and a sprinkle of baking soda barely moves soil pH anyway, and only briefly. Worse, baking soda is sodium bicarbonate: the sodium it leaves behind damages soil structure and is taken up by the plant, so repeated use does harm rather than good. There is no path from baking soda in the ground to a sweeter tomato. (It is the same physiology as the sugar-in-the-soil belief, B-008: fruit sugar is made in the leaves, not delivered from the ground.)
Evidence: not yet confirmed against its 2 sources.
what this rests on - 2 pointers
fruit sugars and acids are set by photosynthesis and cultivar
not by soil pH; sodium from sodium bicarbonate harms soil structure and plant uptake; extension horticulture consensus
When would that grow at your place? →
Cite this page
Milpa Gardens. "Sprinkling baking soda around tomato plants makes the fruit sweeter." Evidence grade: Refuted. https://milpa.garden/beliefs/baking-soda-tomatoes-sweeter-tomatoes/
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.