What Is in Detergent That Might Make Plants Grow?

Phosphate

• Phosphate is the ingredient in some detergents that makes dishes and clothes clean. Phosphate breaks up grease and suspends dirt particles so they don't wind up back on your clothes and dishes. The phosphate keeps your dishes shiny and clothes from looking gray and dingy. Fertilizers contain phosphate, as do some foods, such as soda which uses phosphoric acid to help hold carbonation.

Plant Growth

• Phosphates are an important nutrient for both plants and animals. Living organisms use phosphate to produce organic macro molecules like DNA. In plants, phosphates are considered limiting factors to growth. Aquatic plants, algae and other vegetation will stop growing without phosphate. Large amounts of phosphates in water stimulate algae and plants to grow to problem levels. Detergent use contributes because rinse water contains phosphates that eventually work their way to bodies of water through waste water treatment of industrial processes.

Environment

• If phosphate levels increase enough in a lake or river, plant growth explodes and clogs waterways with algae and plants. This impedes recreational use such as swimming and boating. Phosphate causes other environmental problems also. In temperate climates, during cool weather the plants and algae that grew due to the phosphate die and bacteria that decompose the plants consume all the oxygen in the water. These oxygen-depleted zones do not support aquatic life, including fish. In July 2010, 17 states significantly reduced the amount of phosphate allowed in dishwasher detergent. Previously 8.7 percent of detergent could be phosphate; the level allowed now is 0.5 percent in those states.

Plant Food

• Plants require 16 chemical elements to survive. These consist of two groups: non-mineral, such as oxygen, and mineral. Plants get mineral nutrients from the soil. Phosphorus is a macro nutrient. The macro nutrients have a division of primary and secondary. Phosphorus falls in the primary group along with nitrogen and potassium. The secondary nutrients are calcium, magnesium and sulfur. Plants use large amounts of the nutrients in the primary group, creating the need for fertilization.