Is Sugar Good for Tomato Plants?

Photosynthesis

• Tomato plants make their own sugar in a process called photosynthesis. Carbon dioxide, water and light energy absorb into the plant, go through photosynthesis and result in two products: sugar and oxygen.

Sugar Research Foundation

• Early experiments suggest that applying sugar to a plant can prove beneficial. A 1948 study conducted by the Sugar Research Foundation found that when a 10 percent sucrose solution was applied to tomato plants, once, growth increased and the lifespan of the plant extended -- but only under conditions of high temperatures and low light levels.

Osmotic Effect

• Plant roots, however, cannot absorb sugar molecules, as scientist David Hershey points out. The presence of sugar around the plant roots actually inhibits the absorption of water and nutrients the plant needs to survive through an osmotic effect, Hershey notes. In addition, the the sugar can encourage pests and the growth of soil microbes -- some beneficial, but many harmful.

Genetic & Metabolic Changes

• Research by scientists at Japan's Kyoto University supports the conclusion that sugar is harmful to plants. Experiments with plants show the addition of sugar delays the flowering and production of plants. The scientists theorize that both genetic and metabolic changes occur due to sugar.