Reducing Phosphorus Impacts on Our Waterways

What is Phosphorous?

Phosphorous, along with Nitrogen and Potassium is an essential nutrient needed for plant growth.  These nutrients can be found naturally in the soil as well as in fertilizers, pesticides, animal waste and detergents.

What's the big deal about phosphorous?

Phosphorous is important for seed development, root growth and for maturation of your lawn.  It is, however, a primary water quality concern in Michigan.  An excess of fertilizer on lawns, sidewalks and driveways can make its way into lakes and streams by storm drains or over land when it rains.  As phosphorous adheres to soil particles, erosion can carry it directly into surface waters.  This can cause nuisance aquatic weed growth and algae blooms, effectively choking area waters.  Please, NEVER apply phosphorous fertilizers on lawns adjacent to lakes, rivers, streams or wetlands.  Just one pound of Phosphorous can support the growth of about 750 pounds of algae!

Most soil in our area carries enough phosphorous to support a healthy lawn.  You can have your soil tested to see if your lawn, garden or fields need additional phosphorous.  If additional phosphorous isn't needed, you can purchase zero phosphorous fertilizer.  Fertilizer bags carry numbers giving the proportion of nitrogen, phosphorous and potassium in the mix.  For example, a 22-0-15 mixture has 22 percent nitrogen, 0 percent phosphorous and 15 percent potassium.  Always look for Zero in the Middle!

Tips for applying fertilizer:

• Always leave a minimum three-foot buffer area around lakes and connecting waterways (including ditches and drains!) to ensure fertilizer does not come into direct contact with the water.
• Use a slow-release fertilizer. This type releases small amounts of nutrients over time to ensure that all are absorbed properly and utilized by the plants. Liquid fertilizer quickly infiltrates the surface and groundwater supplies when lawns and gardens are irrigated, or during a rainstorm.
• Slow-release fertilizers generally need to be applied only once during a growing season. No reapplication is necessary, especially when you incorporate native vegetation into your landscape.
• Other Lawn Care Tips 

Did you know that Allegan and Van Buren County, along with other Lake Michigan shoreline counties have adopted ordinances that requires the use of phosphorous free fertilizers on all lawns including residential, commercial and golf courses?  Even more recently (16-Dec- 2010), Michigan adopted a statewide law regulating the use of phosphorous fertilizers on lawns.  For more information and to view these regulations, click here.