Microplastics from washing clothes could be hurting your tomatoes
Scientists say household laundry is a leading source of polyester microfiber and other microplastic contamination in the soil.
Author of the article:Washington Post
Washington Post
Ambrosia Wojahn
Published Jan 22, 2026 • Last updated 18 hours ago • 4 minute read
011526-MICROPLASTICS-TOMATOES_AA7P4AU4LJFYBIQQCA4AYU2Q2M
Workers harvest ripe cherry tomatoes inside a greenhouse in Bonita, Arizona, last year. MUST CREDIT: Anna Watts/For The Washington Post Photo by Anna Watts /For The Washington Post
New research suggests that tiny fibres shed by clothing can harm the growth of cherry tomato plants, with potentially broad implications for agriculture.
Scientists say household laundry is a leading source of polyester microfiber and other microplastic contamination in the soil.
Now a study by researchers at Cornell and the University of Toronto has found that polyester microfibers present in soil can delay development and reduce success rates for cherry tomato plants.
Experts say every load of laundry releases millions of tiny fibres into sewage systems and subsequently into waterways, soil and the atmosphere. Many of these fibres are microplastics, shed from polyester and other synthetic fabrics. Scientists are just beginning to study the implications of this new form of pollution on human health and the environment.
Each year, farmers apply millions of gallons worth of treated sewage sludge on cropland as fertilizer. Even after treatment, the sludge retains roughly 90 percent of microfibers carried from household washers and transfers the fibres and other pollutants into the soil. In some countries, up to 75 percent of cropland is treated using this method, the researchers said.
Natasha Djuric, one of the authors of the study, said her team chose cherry tomato plants because they have a relatively short, 90-day growth cycle and because they’re important for food production.
The study found microfibers can have consequences at every stage of plant development. Researchers observed that the plants grown with microplastics were 11 percent less likely to emerge from the soil, were smaller in size and were several days slower to produce flowers or ripen. The contaminated soil also had lower water retention, which may have led to some of the negative results.
Although the study showed a negative impact on growth, the scientists said more research will be needed before drawing conclusions for agriculture in general.
“Sometimes microplastics can have a positive impact on soil or plant properties, and sometimes it could be negative,” Djuric said.
Research on microplastics and plant growth is still in the early stages, the scientists said. And much of our knowledge of microplastic pollution centers on ocean-dwelling organisms.
“I think for a long time, our intuition was even if microplastics end up on the land, they’re going to run off into water bodies and all of that ultimately leads into the ocean,” Djuric said. “So now that we’re looking, we’re realizing that there’s a significant chunk of microplastics that end up interacting with terrestrial ecosystems for long periods of time.”
While the tomato study sheds light on the potential of microplastics to harm plants, some scientists are skeptical of its approach.
Willie Peijnenburg, a professor of environmental toxicology at Leiden University in the Netherlands, said the percentage of microfibers used in the study was much higher than any concentration he and his colleagues have observed in the field.
Peijnenburg has found the primary way plants are exposed to microplastics is through the air. Plants can absorb the particles from the atmosphere through tiny holes in their leaves, called stomata. The sources of the airborne pollutants could be virtually anywhere where plastic is stored, produced or broken down, he said.
“What we’ve found is that it’s very difficult to get real effects on plants in [soil] studies like this,” Peijnenburg said.
Djuric said that while the concentration of microfibers used in the experiment was on the higher end, the level of contamination in soil varies greatly by location and other factors, and that researchers often underestimate the amount of microfibers present in the environment.
Shelby Riskin, an associate professor of evolutionary biology and ecology at the University of Toronto and a co-author of the tomato study, noted that other research on crops and microplastics found some plants actually grow better when exposed to the pollutants, but said it’s difficult to pinpoint the exact cause.
Mary Beth Kirkham, an agronomy professor at Kansas State University who was not involved in the study, said she has seen positive results. She described an experiment in which corn grown with microplastics in the soil had higher protein levels than corn grown without the contaminants.
“The corn grown with microplastics in the soil had more nitrogen in it, which led to more protein,” Kirkham said.
But the increased protein from the contaminants does come with trade-offs, Kirkham said. Microplastics are a known carrier of heavy metals, which if consumed can have negative health effects.
While experts say regulations and policy changes are necessary when it comes to reducing contaminants in the environment, there are steps we can take as individuals.
Lisa Erdle, director of science at 5 Gyres Institute, an advocacy group, said there are a number of ways people can reduce their personal microfiber output.
Avoiding synthetic fabrics whenever possible can reduce the release of microfibers. And buying vintage or secondhand clothing can help, Erdle said, because new garments tend to shed significantly more fibers than used garments. Temperature also matters, Erdle said. Washing in cold water is the best way to limit the shedding of microplastics from your clothing.
Since wastewater from washing machines is a primary source of microplastics, scientists are working on ways to keep the contaminants out of the sewage system. Chelsea Rochman, another co-author of the tomato study, has explored new filters that can capture roughly 90 percent of microplastics released by a load of laundry.
“Microplastics are an ever-evolving issue,” Erdle said. “Although we’ve been aware of them for a long time, we still have a lot to learn about their effects.”
New research suggests that tiny fibres shed by clothing can harm the growth of cherry tomato plants.
torontosun.com