Somewhere along the way, the perfect vision of the American lawn became a lush green carpet with absolutely no weeds, no clover, and no color variations. As a nation, we decided our yards must look picture perfect. For many, achieving that picture involves the liberal use of commercially sold chemicals — fertilizers, insecticides and weed killers. And while homeowners may achieve their dream of the “perfect” lawn by using these chemicals, the achievement comes with a price often paid by our water, wildlife, and soil.
Commercial fertilizers typically contain nitrogen, phosphorous, and potassium. Nitrogen is an important lawn nutrient, but it can contaminate our groundwater with nitrates. In research studies scientists have concluded that water with more than 10 parts per million (mg/L) nitrate-nitrogen can cause methemoglobinemia, an inability to use oxygen in infants. In addition, children, between the ages of 12 and 14 have shown delayed reactions to light and sound stimuli from drinking nitrate-contaminated water. As most Adams County residents get their drinking water from groundwater wells, this should be of concern. And while most wells in Adams County are currently within safe levels as set forth by the EPA, recent sampling of groundwater wells in Adams County found that several wells are producing water with median groundwater nitrate content over the 10 parts per million threshold.
If you feel you absolutely must have a picture-perfect lawn, there are some things you can do to lessen the effect lawn chemicals have on water quality. First, have your soil tested before applying chemicals to your lawn. Your lawn may not need additional nitrogen, phosphorus, or potassium. Adams County is fortunate to have a robust Penn State Cooperative Extension office, 670 Old Harrisburg Road, Gettysburg, where you can easily pick up a soil test kit and have the results provided by the Pennsylvania State University.
Second, consider using compost rather than inorganic chemicals to feed your lawn and improve the health of the grass. Compost, which is available at most garden centers, provides an organic, slow-release fertilizer and actually enhances the health of the soil. Healthy soil equals healthy grass.
From 2003 to 2015, a team of researchers at the University of Wisconsin-Madison studied two fields to which were applied either compost or inorganic fertilizer. Their findings were significant. Specifically, compost helped keep the soil pH in the healthy range, while inorganic fertilizer made the soil more acidic (not ideal for growing grass). In addition, compost increased the soil’s organic carbon levels and water-stable aggregates when compared to inorganic treatments. More carbon means better soil structure which means better grass. Increased water-stable aggregates mean less erosion which means fewer chemicals washing into neighboring waterways.
Finally, apply chemicals at the correct time. Read the label carefully and always apply products when your grass can actually use them. Most lawn grass in Adams County begins going dormant in August. If you apply fertilizer now, it will simply run off into neighboring waterways, or leach into the groundwater (and perhaps your well). If you do apply fertilizer, never apply it before a heavy rainfall is expected. Of course, you can also make peace with your lawn and skip applying chemicals altogether. The planet, and especially our watershed, will thank you for it.