Some organically grown tomatoes appear to have higher levels of potent antioxidants, and the reason may be in the fertilizer, NPR reports. Researchers at UC Davis running tests on levels of the antioxidants, known as flavonoids, found 79%-97% higher flavonoid levels in the organic tomatoes.
One explanation now being tested is that the nonorganic growing process involves commercial fertilizer with added soluble nitrogen, which plants absorb quickly for maximum growth. The organic process uses manure and compost for fertilizing; both deliver nitrogen more slowly. The plants may use that extra time “toward making secondary plant metabolites”—like flavonoids, speculates one researcher.