When I signed up for the course “Lawns in the Landscape: Environment Hero or Villain?” at the University of Maryland I had suspicions, even after reading this description: “Examination of the lawn as an element in the anthropogenic landscape and its influence on global warming, regional air and water quality, ecological diversity, mammalian pesticide exposure and consumptive water use…Policies that incentivize lawn alternatives or changes in lawn management behavior are discussed.”
My suspicions were twofold – what if the professor is a tool of the turfgrass industry? Or conversely, what if he’s a tool of the anti-lawn movement? I was relieved to learn that Dr. Mark Carroll is neither of those. He’s a turfgrass researcher, and one of the best teachers I’ve ever had.
One more hesitation I had about the course is one I’m embarrassed to admit – that it’s been my most-covered topic for 20 years so I could probably taught the course myself! Hahahahahaha! See, I imagined the content would be similar to information directed to the public, but no, this is science! Here’s what was covered, per the syllabus:
- History of lawns (2 lectures)
- The turf industry
- Cultural norms (a low point that I ranted about here)
- Turfgrass growth and development
- Soils and fertilizers
- Garden equipment
- Best management practices
- Climate change and carbon sequestration
- Water restrictions and landscape use
- Fertilizers (3 lectures)
- Pesticides (3 lectures)
- Lawns and pollinators
- Clover
- Organic lawn care
- Synthetic turf
Whew! And boy was I glad I was auditing because math was involved! Students had to calculate how much carbon the campus lawn sequesters and emissions from gas-powered lawnmowers. But it was a relief to learn about lawn from a scientific perspective, from an objective researcher, one who’s involved in writing state laws protecting the Chesapeake Bay – the most restrictive in the U.S. Dr. Carroll quickly assuaged my fears that he had any sort of agenda.
I hope that prepares you for some news that may shock you:
Lawns Have Benefits!
Since there’s about 50 million acres of turfgrass in the U.S., it’s good to know that it provides some important ecosystem services:
- Filters air pollutants
- Erosion control and dust stabilization “It’s particularly good at stopping initial movement of water down a slope.”
- Cools surface temperature
- Reduces noise pollution
- Reduces pests like snakes, rodents, mosquitos and ticks.
- Captures and stores carbon (Turfgrass roots die off within a year – which increases organic matter in the soil.)
- Catches, filters and conserves surface water to reduces run off of contaminants.
- Cultural and recreational benefits (Yes, benefits to humans are included in definitions of eco-services.)
The National Park Service agrees, adding that “Turfgrass Supports Bioremediation: Pollutants, such hydrocarbons and heavy metals, that are detrimental to the health of people, plants, and animals, often end up in our soil where these substances can be broken down by bacteria, fungi, and other microorganisms. A healthy stand of turfgrass possesses an extensively fibrous root system, providing both the habitat and energy source for these microbial populations to be much more productive than other plant systems.”
Cornell adds one more to the list – “Increases home selling price.”
Lawns are sure better than some alternatives – like wood chips or pavers. (AI-generated images.)
Misinformation #1: Lawns Have No Environmental Benefits At All
I’m not the only one noticing the problem in current lawn messaging: “Lawns seem to draw as much irrational hate as they do love these days,” said Paul Robbins, dean of the Nelson Institute for Environmental Studies at the University of Wisconsin-Madison and the author of “Lawn People: How Grasses, Weeds, and Chemicals Make Us Who We Are.” He added, “Green lawns, as much as brown ones, are now seen as a moral failing.” Source: New York Times
From Homegrown National Park
Much of the irrational hate is due to claims that lawns have “zero benefit” environmentally, frequently asserted by entomologist and native-plant advocate Dr. Doug Tallamy and many people who quote him. I’ve heard him say in talks or interviews that lawns perform “none” of the services that properties should provide. (One source is Homegrown National Park.)
Why make claims that are demonstrably false?
My old green-enough, stormwater-filtering lawn.
I first became leery of anti-lawn attacks back when I had a lawn on a fairly steep incline and could see that even during a strong rain event, the rain did indeed filter through the grass. So the often-repeated claim that it was no better than asphalt at preventing run-off I recognized are BS. (Just last week a local activist repeated that claim to me and I knew not to waste my breath trying to correct her.)
You know what DOES cause turfgrass (and other plants) to fail to capture stormwater? The compacted soil or construction rubble it’s planted in. That lawn of mine was growing in real topsoil that had never been damaged by heavy equipment.
These slides from class illustrate a missing point in the whole anti-lawn argument – the major role played by the soil or lack thereof. I would never have guessed the lawn on the right was so self-sustaining. (This is from a study by Dr. Carroll.) Soil compaction is often found to be the cause of poor lawn performance leading to over-use of fertilizers and herbicides.
Misinformation #2: Lawn Care HAS to be Harmful, and High-Maintenance
Even more prevalent is the claim is that lawns require vast inputs – pesticides, harmful fertilizers and supplemental water.
From a talk by Mark Richardson, New England Botanic Garden at Tower Hill
Here’s an example, from the Scientific American: “There are a lot of ecosystem services that lawns can offer, unlike a hard surface such as cement or asphalt. Lawns sequester atmospheric carbon, produce oxygen and prevent erosion. But lawn upkeep takes resources: water; fertilizer, pesticides and herbicides that enter groundwater and runoff water; and mowers that burn fossil fuels and emit gases that heat up the atmosphere. ”
Kudos (I guess) to Scientific American for acknowledging lawn’s ecosystem services and that it’s better than cement.
And here’s Margaret Renkl in the New York Times:
Nearly everything about how Americans “care” for their lawns is deadly. Pesticides prevent wildflower seeds from germinating and poison the insects that feed songbirds and other wildlife. Lawn mower blades, set too low, chop into bits the snakes and turtles and baby rabbits that can’t get away in time. Mulch, piled too deep, smothers ground-nesting bees, and often the very plants that mulch is supposed to protect, as well… Turf grass requires immense amounts of water and poison to maintain.
But what I learned in class is that most homeowners in the Chesapeake Bay watershed don’t use pesticides on their lawns at all. And in the suburban DC neighborhoods where I’ve lived, you can tell herbicides aren’t used because the lawns have plenty of weeds. They’re “freedom lawns” or “green-enough” lawns, like the one I used to have. And in this region fungicides (the other pesticides they’re referring to) are used on golf courses but rarely on residential lawns.
What homeowners actually DO is mow, and most do apply fertilizer, but rarely more often than once a year. Here and and increasingly elsewhere, there are strict limitations on the types, amounts and timing of fertilizer application. We’re no longer allowed to top-dress lawns with compost due to its high phosphorus content! Dr. Carroll was on the research team recommending Maryland’s restrictions – the strictest in the U.S. (I’ll have more on the surprisingly complicated topic of lawn fertilization in a separate post.)
Finally, about the claim that lawns need “excessive amounts of water.” Well sure, in arid climates lawns require outrageous amounts of that scare resource. But here in Maryland we get roughly the right amount of rain to keep our lawns green (about 1.5″ per week) and when we do have periods of drought, we can just let them go dormant until the rains come again.
And let’s not forget that lawns don’t have to be perfect monocultures like the one shown above. You can easily add some clover and other flowering plants that support pollinators.
A More Impactful, Pro-Environment Message? Reduce Your Lawn AND Get Rest of it Off Drugs!
Anti-lawn messengers could do the most good by meeting people where they are – wanting or needing to keep their lawn, or some of it. So in addition to encouraging people to reduce their lawns (with facts, inspiring images, and no misinformation), an even more impactful message is to stop using pesticides. And why not include: follow fertilizer best practices and let your lawns go dormant during summer.
There’s plenty of good information to help people switch to “eco-friendly” lawn care, like Cornell’s “Just Do Less” message. And there’s Oregon State’s “How to make lawns eco-friendly,” which lists even more benefits of turfgrass and is simply helpful:
Lawns might get a bad rap but provide benefits such as play space for kids and pets, erosion control and allowing line-of-sight at intersections. They are also a low-cost, easy-maintenance ground cover. There are thoughtful ways to keep a lawn as part of your landscape while balancing climate change concerns.
What’s stopping the very vocal anti-lawn messengers from following the science and broadening their appeal to include eco-friendly lawn care? I’m honestly asking, because I don’t get it.