Clean Lake Tip: Don’t ‘P’ on Your Lawn

Phosphorus (P) is one of the primary water quality issues facing Lake Champlain—the same nutrient that feeds our lawns and gardens fuels cyanobacteria blooms. Thanks to advocacy from the Lake Champlain Committee (LCC) and partners, in 2012 Vermont and New York passed restrictions on P in lawn fertilizer. 

Fourteen years later, there is still work to be done: the restrictions on fertilizers include exceptions for new lawns and for phosphorus-deficient soils. This means that many retailers still sell phosphorus-containing fertilizers, and for people not aware of the restrictions, it is easy to add unnecessary “P” to their lawn by accident. Having clear signage at lawn and garden stores helps inform customers of the importance of using phosphorus-free fertilizers.  

This is where you come in! LCC needs volunteers to visit their local lawn and garden stores, check out what kind of fertilizers they’re selling and how they’re displayed, and share signage and educational materials with store personnel. You can do a quick assessment at one store while running errands, or you can spend an afternoon visiting multiple stores.  

LCC will provide you with a full Phosphorus Investigator (“P”I) toolkit, including:  

• A step-by-step guide on doing a “P”I assessment, including tips on engaging store personnel  
• Educational materials to share with retailers  
  • Signage about New York and Vermont state laws for phosphorus in fertilizers  
  • Don’t “P” on Your Lawn rack cards, holders, and buttons   
• Background material for you, including a printout of our “Lake Look” column detailing the importance of keeping phosphorus out of lawn fertilizers  

Please contact Eileen Fitzgerald at eileenf@ lakechamplaincommittee.org or call (802) 658-1461 if you are interested in becoming a "P"I and we can set up a time for you to pick up volunteer toolkit(s).

Want to help out without volunteering? You can adopt these lake-friendly lawn care tips and share them with your neighbors.

1. Use only phosphorus-free fertilizers—look for the zero 

The three numbers on a fertilizer bag indicate the nutrient percentages of nitrogen, phosphorus, and potassium (N-P-K) in that order. A zero in the middle means it’s phosphorus-free; for example, 22-0-15. Fertilizers sold in lawn and garden stores should be clearly marked as either “lawn fertilizers” which should not contain phosphorus, or as “lawn starters” which usually do contain phosphorus. 

 2. Take a soil test—learn about your lawn 

A soil test can tell you about the nutrient levels, organic content, and pH (the soil’s acidity or alkalinity) of your lawn or garden area and what you need for healthy plant growth. The University of Vermont Agricultural and Environmental Testing Lab offers basic soil testing.  In New York State, your county’s local office of Cornell Cooperative Extension (CCE) can help. 

 3. Fertilize once a year—apply in the fall, not the spring 

The application of fertilizer in the fall helps grass survive the winter and prepares it for successful growth the following spring.  

 4. Water less—grass is hardy 

Even without watering, grass will survive drought by going dormant. Water in the early morning, when the air temperature is cooler, and only when it rains less than one inch during the week. 

5. Mow higher—raise the blade 

Maintain a grass height of three to four inches and cut off no more than 1/3 of the blade height during each mowing—this allows grass roots to deepen which is good for soil health and helps prevent runoff. Leave grass clippings on your lawn to build nutrient and organic matter. 

6. A friendly flower reminder—“weeds” can be beneficial 

Flowers like common dandelion, violets, and white clover offer numerous benefits: dandelions and violets provide food to pollinators and clover roots contain nitrogen-fixing bacteria—a natural way to fertilize your lawn if it’s lacking nitrogen. These “weeds’ also have deeper roots than regular turf grass, which is beneficial for soil health and water retention.