Is Lawn Fertilizer Bad for You? The Chemicals to Avoid
For people with yards, keeping grass lush can often feel like a full-time job: planting, treating, mowing, bug-killing, watering—and repeating. The many services and products that this industry offers, led to a global revenue of $16.8billion in 2020 according to analytics company Allied Market Research.
The roots of lawn care can be more dangerous than the appearance of a green lawn may suggest. After World War II, fertilizer became more popular as factories producing large quantities of nitrogen to bombs used that capacity for agriculture. Around the same time, the insecticide DDT—which writer and conservationist Rachel Carson famously called out for its detrimental environmental and health impacts in her book Silent Spring—also made its way into everyday use.
Pesticides have improved over the years, and there are now safer options. However, many backyard products still contain potentially dangerous chemicals. The toxicants are linked to cancer, as well as other diseases in pets. The environment can be affected by nutrient runoff from yards.
Here’s what experts say people should do to keep their grass, and themselves, healthy—including some chemicals to consider using with caution, or avoiding altogether.
What are the differences between lawn treatments?
There are many products that can be applied to lawns. These include fertilizers, insecticides and pesticides. Each one has a unique function. Fertilizers add nutrients to soil. Herbicides, insecticides, or pesticides can target plants, animals, bugs and weeds.
To figure out what—if anything—you want to do to your lawn, people should start by asking themselves, “What is the problem and how can I treat that problem?” says Jennifer Sass, senior scientist at the environmental organization National Resources Defense Council (NRDC). This will allow them to address the problem at hand.
A soil test, which measures pH, nutrient levels, and more, can be a good place to start, suggests Chrissie Segars, a turfgrass specialist at Texas A&M University. Most states offer free testing through universities and extension programs. At Texas A&M, a soil test starts at just $12, and while Segars says getting one every year is ideal, she acknowledges that every few years is probably more realistic for most people.
Is lawn fertilizer, or any other treatment, a risk to your health?
A number of chemicals in lawn-care products have come under scrutiny in recent years over their potential health impacts—particularly the herbicides glyphosate and 2,4-Dichlorophenoxyacetic acid (more commonly known as 2,4-D). Ingestion, skin contact, and inhalation can all lead to exposure. The U.S. Centers for Disease Control and Prevention states that exposure to both one or both can cause serious health problems, including nausea and vomiting.
Roundup is a widely-used weed killer. Glyphosate, the active ingredient of Roundup is what is most commonly used. While the U.S. Environmental Protection Agency (EPA) found “no evidence that glyphosate causes cancer in humans” when it reviewed the available data in a 2020 report, the World Health Organization’s (WHO) International Agency for Research on Cancer (IARC) classifies the compound as “probably carcinogenic to humans.” One 2019 meta-analysis of studies on the topic found that exposure to glyphosate was associated with an increased risk of Non-Hodgkin lymphoma, a type of blood cancer, in humans.
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Many communities have begun to ban or restrict the use of Glyphosate in their state. Some countries have also taken similar steps, including some in Europe, such as France, Portugal, Austria and France. The emerging concern has been accompanied by mounting lawsuits—including a class-action consumer suit against Bayer, the manufacturer of Roundup, alleging that Roundup did not have adequate cancer warnings. Bayer settled the case for $23 million. Bayer recently announced it was ending residential sales of glyphosate-based products in the U.S.A in 2023.
There are some experts who also worry about 2,4 D, another chemical commonly found in many herbicides. The EPA says that 2,4-D “generally has low toxicity for humans,” while WHO lists it as a “possible” carcinogen, though the evidence in humans remains “inadequate.” Some research has linked occupational exposure to 2,4-D—in farmers and professionals who apply herbicides—to a higher risk of lymphatic cancers, particularly Non-Hodgkin lymphoma. There have been many studies that link 2,4-D and cancer in pets. A 1991 paper found that the chance of developing malignant lymphoma from dogs exposed to four- or more annual doses of 2,4–D. Sass advises that while research is still ongoing, it’s best to be cautious and avoid getting 2,4-D.
Sass says there are also concerns about organophosphate insecticides like malathion or chlorpyrifos. These can harm nerves and cause nausea, headaches, sweating and vomiting. “Kind of like having a panic attack,” she says. “For a pet, they can be lethal.”
“Many of the health impacts are under the intended conditions of use, and according to the label,” says Sass. The IARC, however, says that the evidence of cancer in humans from real-world exposure to glyphosate is “limited” and the CDC says “the levels of 2,4-D found in the environment are lower than levels known to cause health problems.”
Segars claims that users should read the instructions on lawn-care products and follow them. “Doing your best to follow the label will reduce your risk of being sick,” she says. It is important to read the labels carefully, including the amount of product that should be applied and when the lawn can be used again. Calculus may also be affected by wind speed, rain and other factors. As for when to return, she says most products are safe once they’ve dried, and that waiting 24-48 hours after an application is a good rule of thumb if a time isn’t given.
“Wear the long sleeves, wear the long pants, wear the gloves [during application]”, Segars advises. “Always read the bags.”
Is lawn fertilizer and other treatment bad for the environment
Fertilizer is a major environmental concern for scientists because rain can wash it from farmers’ fields or neighborhood lawns into waterways, which can eventually carry the pollution into oceans. Despite the fact that fertilizer is most commonly used in agriculture, it can also be found in homes.
Nitrate and phosphate are the two primary ingredients of fertilizer. They are meant to stimulate plant growth. But when they get into waterways they can cause algae—including toxic algae—to proliferate and oxygen levels in the water to plummet, making it difficult for much aquatic life to survive. Pollution from crop fertilizers, for example, has contributed to a massive “dead zone” in the Gulf of Mexico.
“You want to minimize the amount of nitrogen,” says Jim Galloway, a biogeochemist at the University of Virginia, though he notes that agricultural rather than residential use is the primary area of concern. “Lawns are a really, really tiny part of the question.”
It is also an essential component in ammonia. This is because it is made from fossil fuels, and contributes to global warming. This is also sometimes explosive. Also, unabsorbed nitrogen could lead to the release nitrous oxide which can be 300 times as potent than carbon dioxide.
The effects of other lawn care treatments on wildlife can also be significant. Insecticides containing neonicotinoids (often referred to just as “neonics”) are popular because they’re water soluble—meaning they soak into the soil and get into the moisture absorbed by plants, thereby increasing plants’ resistance to pests. Recent research has demonstrated that neonics are harmful to honeybees. These bees provide invaluable pollination service. The chemical has been shown to impact bees’ ability to forage and contributes to colony collapse.
Even lawn care that is chemical free can cause environmental damage due to emissions produced by gas-powered mowers.
How can I make my lawn healthier?
You can reduce lawn care’s impact on the environment by having less grass. That may mean replacing swaths of grass with native plants, or designing landscapes that limit the need for irrigation (also known as “xeriscaping”). Even leaving your grass a bit longer can help, Sass says, “If you do less work, the longer lawn will choke out the weeds.”
Ryan Anderson, the IPM Institute of North America community integrated pest manager, suggests that you avoid products with glyphosate 2,4-D and organophosphates. He also says that people buying fertilizer sometimes don’t realize that there may be herbicides already mixed in, such as with so-called “weed and feed” blends—so double check before leaving the store. There are also some lower risk products, such as Fiesta, that he points people to if they insist on applying weed or pest control—though he warns that they can be expensive.
Sass says that, unless someone has a great deal of experience with gardening, it is possible to prevent unnecessary problems and accidents by avoiding products they must mix from concentrate. “I hope they are buying those products that are ready-mixed,” she says. People could also consider bug repellent instead of applying mosquito treatments to lawns. (“Try not to apply directly on the skin,” she says, and aim for clothing instead.)
Anderson suggests natural compost for fertilizer alternatives. This can be applied to areas that are in dire need of nutrients. Anderson suggests that aeration can also be used to maintain a healthy lawn. You can rent an aeration machine from your local hardware store. These machines insert small cores into the lawn. Or you can manually do it using special tools, or a simple pitchfork. He says the process can help to revive soil that has been compacted. It should only be done once per year.
“All those steps are best in the fall,” says Anderson, though he adds that the process may take time to show results, especially if a lawn has become accustomed to chemical treatments. “If you used it a lot in the past, there’s a risk of your grass feeling stressed out,” by a sudden lack of treatments, he says. “It’s not going to happen overnight”—but a healthier approach to lawn care is worth it.
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