Because almost every neighborhood in the U.S. hosts a series of nearly identical patches of greenery, the prevailing assumption among urban ecologists has been that lawn care behavior is similar across the nation.
But in a new study on lawn care habits published in the Proceedings of the National Academy of Sciences, a research group funded by the National Science Foundation notes that no one has actually bothered to test whether irrigation and fertilization practices are uniform. "To date, the social and natural sciences literatures on lawncare have tested for the homogeneity of biophysical outcomes from lawncare practices, assuming – not testing – an underlying homogeneity of lawncare practices," the authors write.
The American obsession with lawns has fueled a $40 billion industry, and excessive use of water and fertilizers "has emerged as a major concern for carbon, nitrogen, phosphorus, and water flows," the authors note. (According to The Week: "The Environmental Protection Agency estimates that one third of all water from public sources goes toward landscaping—most of it on grass.") In hopes of informing recommendations for more sustainable practices, the research group recently attempted to gauge just how homogenous lawn care habits are with a survey of 9,480 residents in Boston, Baltimore, Miami, Minneapolis-St. Paul, Phoenix, and Los Angeles.
Is it smarter to just outlaw new lawns altogether, especially given that they're just cosmetic overkill?
The results indicated that nearly 80 percent of the respondents irrigated their grass, and 64 percent used fertilizer. But the researchers conclude that there's "limited evidence for complete homogenization," meaning differences were apparent both across and even within different cities. The utopian lawn practices long bandied by pushy neighbors have not been as widely adopted as thought.
Los Angeles and Miami, for instance, have similar rates of lawn fertilization, but fertilization within each respective city varies according to population density (urban, suburban, rural). Los Angeles and Phoenix had similar rates of irrigation, but variance within those cities can be explained by socioeconomics.
Designing sustainable plans going forward will necessitate a more micro-targeted approach. "The results suggest that a one-size-fits-all policy for trying to persuade U.S. residents to manage their lawns less intensively will not work," lead author Colin Polsky, an associate professor of geography at Clark University, wrote in an email. "Such a policy needs to be grounded in the factors influencing the behaviors, which ... vary with climate and social, economic, and demographic characteristics of households."
Is it smarter to just outlaw new lawns altogether, especially given that they're just cosmetic overkill? Polsky believes that approach has been workable in drier climates, like Las Vegas, but might be unnecessary in wetter ones.
Peter Groffman, a microbial ecologist at the Cary Institute of Ecosystem Studies and a co-author, was more opposed to a ban, pointing to lawn values like "cooling in the summer and heating in the winter, biodiversity, soil carbon and nitrogen retention, stormwater infiltration, aesthetics, [and] outdoor recreation," he wrote. "So people are certainly deriving benefits from their lawns and any policy to outlaw lawns or to mandate particular types of lawns needs to consider the full suite of costs and benefits."