Phosphorus is a common nutrient found in lawn fertilizer and is one of the most problematic pollutants in stormwater. It wreaks havoc on aquatic ecosystems, particularly in streams and lakes. High levels of Phosphorus result in excess algae growth that depletes the water of oxygen, drastically reduces water quality and ultimately can cause fish kills.
It is important to decrease the amount of Phosphorus in order to improve watershed health and for most yards phosphorous is often unnecessary. A soil test will be able to determine whether a fertilizer with Phosphorus is needed.
There are three numbers on fertilizer bags for the Nitrogen-Phosphorus-Potassium nutrient amounts.
A Phosphorus-free fertilizer will have a zero as the middle number. Regardless of the type of fertilizer used, it is important to apply the minimal amount of fertilizer necessary.
It is also recommended that the fertilizer is only applied once a year, early fall is the best time to do this.
Make sure to sweep up leftover fertilizer on sidewalks and driveways and dispose of it properly in the garbage.