PLANET Position Statements
Application of Lawn Care Materials Around Wells, Streams, and Ponds
Current research indicates that the potential is quite low for fertilizers and pesticides applied to turf to leach downward to ground water or to run off into storm drains or other non-target areas. Research at Cornell University, Pennsylvania State University, Ohio State University, and the University of Rhode Island points out that leaching and runoff from turf is not a major concern, provided normal management practices are followed, moderate rates of fertilizer are used, and pesticides are applied judiciously and according to label directions.
Unlike an agricultural setting where fertilizer and pesticides are often applied to fallow soil, applications to turf are made to an actively growing crop that is capable of using those products immediately. Thatch, a layer of organic matter at the soil surface on lawns, can significantly reduce runoff potential further. And turf’s defense, extensive, and fibrous root system minimizes leaching of fertilizer and pesticides out of the root zone.
Many potential sources can cause nitrogen contamination of ground water. These include leaching from improperly maintained or malfunctioning septic tanks, construction sites, deterioration and release of nutrients from aging sewer lines, and animal feed lots and pet excrement. These sources of nitrogen have been shown repeatedly to be a larger concern than normal lawn fertilization in ground water and surface water contamination.
Small amounts of fertilizer and pesticides applied to turf may find their way to ground water under some extreme conditions. Applications around wells with cracked casings must be avoided, as well as applications over shallow, gravel-packed wells.