Adding sugar or molasses to the soil makes tomatoes and other fruit sweeter.
Sugar in the soil won't sweeten your tomatoes. Fruit sugar is made in the leaves by sunlight. For sweeter fruit, you want a sweet variety, full sun, healthy foliage, and ripening on the plant (a little less water as it ripens helps concentrate it).
What is actually known
The sugar in a ripe tomato is made in the leaves by photosynthesis and moved into the fruit as it matures; extension sources call sugar-in-the-soil sweetening fiction. How sweet a tomato gets depends on the variety, on ripening on the plant, and on the balance of leaves to fruit, and holding back water as the fruit ripens can raise its sugars. The usual explanation that roots cannot absorb sugar at all is too strong. Roots do have sugar transporters, and in a lab a genetically engineered tomato line grown in glucose-fed soil made sweeter fruit. But nothing we have read shows sugar or molasses sweetening an ordinary garden tomato.
The evidence
Evidence: not yet confirmed. It is cited to 5 sources, which a person has yet to read.
What this rests on - 5 pointers
Fiction- Tomato plants can’t absorb sugar in the soil, they produce it through photosynthesis.
Sweetness depends on the leaves of the plants. As the fruit matures, sugar is transferred from the leaves to the fruit.
Home gardeners have a significant advantage by allowing tomatoes to ripen directly on the plant.
When grown in soil, supplemented with glucose, tomato fruits from the overexpression lines had significantly higher levels of glucose and other sugars
Deficit irrigation could increase the total soluble solids, reducing sugars, organic acids, vitamin C, and lycopene content of tomato fruits
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Cite this page
Milpa Gardens. “Adding sugar or molasses to the soil makes tomatoes and other fruit sweeter.” Evidence grade: Refuted. https://milpa.garden/beliefs/sugar-soil-molasses-tomatoes/
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