Ecologically Sound Lawn Care for the Pacific Northwest
Findings from the Scientific Literature and Recommendations from Turf Professionals
ABSTRACT: Turfgrass management since 1940 in the U.S. has been characterized by intensive use of synthetic chemicals including water-soluble fertilizers, herbicides, insecticides, and fungicides. Conventional practices also generate solid waste (through removal of grass clippings) and hazardous waste (leftover chemicals), and use large amounts of irrigation water, which may be wasted through overwatering or runoff.
A review of current science suggests that these practices may be harmful to human and wildlife health, and also negatively impact the turfgrass ecosystem, contributing to significant declines in populations of beneficial soil organisms, soil acidification and compaction, thatch accumulation, and diminished resistance to diseases. Interviews with turf professionals around the Pacific Northwest region and a review of scientific and technical literature indicate that a proven alternative approach exists. It is based on observation of the entire soil and grass ecosystem, appreciation that turfgrasses are sustained by the activities of soil-dwelling organisms, and understanding that this grass community is a dynamic equilibrium among many plants, invertebrates, and microbial organisms. This equilibrium can then be shaped to support the natural vigor of the grass plant and the beneficial soil organisms, and to minimize pest problems, by application of proper cultural practices.
Recommended practices include: setting realistic expectations for lawn appearance and tolerating a few weeds; proper site selection and soil preparation; using site-adapted grasses; mowing higher; leaving clippings; correcting soil deficiencies; moderate use of natural or slow-release fertilizers; irrigating deeply but infrequently; renovation practices including aeration, over-seeding, and compost topdressing; and use of the integrated pest management process.
Key Words: turfgrass, lawn, pesticides, herbicides, earthworms, biological controls, IPM, grasscycling, compost, natural fertilizers, ecological lawn care.
David K. McDonald
Community Services Division
Resource Conservation Section
Seattle Public Utilities