Synthetic vs. organic lawn care products by the numbers
Synthetic and organic lawn-care products are defined by a series of three numbers (e.g., 22-05-16).
First number: Percentage of nitrogen, which helps “green” a lawn by making chlorophyll. The higher the percentage, the less fertilizer you need ?to add — and buy. Best are fertilizers with a mix of water-soluble and water-insoluble nitrogen.
Second number: Percentage of phosphorous, which helps promote root growth and prevent diseases. Some cities and states have banned or restricted fertilizers with phosphorous because of evidence that it can cause toxic algae bloom and kill fish when ?it flows into freshwater streams, rivers or lakes.
Third number: Percentage of potassium, which helps grass blades withstand stress and hold more water, reducing the need for frequent watering.