ELIMINATE POLLUTANTS

6. Use Phosphorus-Free Fertilizer

Phosphorus & Water Quality

What is phosphorus?​

Phosphorus is a natural element and an essential nutrient for plant growth, but is found only in small amounts in lakes and streams. Even small increases in phosphorus can have a devastating impact on the water quality of a lake or stream. Increased phosphorus can stimulate algae and excessive plant growth. Boating, fishing, and swimming can become difficult and lake property values and tourism can also be negatively impacted.

Green and gross​

Excess phosphorus can lead to an explosion of algal growth in the lake. A single pound of phosphorus can support more than 1,100 pounds of algae in​ Twin Lakes!

More phosphorus, less fish​

As algae die and decay, water is robbed of dissolved oxygen. This can devastate fish populations if it occurs for a long period of time or the fish have nowhere else to go.

Where does phosphorus come from?​

Phosphorus has many sources. Small amounts of phosphorus exist naturally in lakes and streams, but human activities from residential and agricultural areas contribute a significant amount of phosphorus. 

Stormwater runoff travels across land, picking up phosphorus from fertilizers, eroded soil particles, septic systems, and pet waste along the way and discharging it into nearby streams and the lake.

Use Phosphorus-Free Fertilizer

What do I look for?​

The three numbers in fertilizer bags show the​ N-P-K nutrient analysis. The middle number is the phosphate (phosphorus) content. A “zero” in the middle means it is phosphorus-free.​

Will phosphorus-free fertilizer keep my lawn green and healthy?​

Yes! Soils in most parts of PA already have an adequate​amount of phosphorus to grow a healthy lawn. In these instances, adding more phosphorus with fertilizer is not needed and will not benefit your lawn.

How do I find out what my soil needs?​

Most lawns in the Twin Lakes watershed do not need a fertilizer with phosphorus. Homeowners can learn about what their lawns may need​ for proper application of various nutrients with a soil test through the Soil Testing Laboratory at Penn State University Extension.

Besides being lake-friendly - It’s the law!​ (at least in Pennsylvania)

Since 2023, PA State law:​

  • Generally prohibits the use of phosphorus-containing lawn fertilizer unless you are establishing a new lawn or repairing turf areas;​

  • Limits application rates of Nitrogen, based on fertilizer type;

  • Prohibits the application of fertilizer onto an impervious surface, or onto frozen ground;​

  • Prohibits the application of lawn fertilizer within 15 feet of a water body;​

  • Prohibits the application of any lawn fertilizer between December 15 and March 1, or when the ground is frozen or covered by snow;

  • Requires education and outreach programs for homeowners and professionals.