Your Garden’s New Enemy: How Microplastics Are Hurting Your Houseplants

(and Your Tomatoes, Too)

Your favorite plant might be struggling for a reason you can’t even see.

Figure 1: Home Garden

Your BFF (Best Floral Friend)

You water them. You talk to them. Some of them even have names. Whether you’re the proud parent of a thriving Monstera named Marvin or a tomato plant that’s taken over your balcony like a jungle king, chances are you care deeply about your green companions. But what if we told you that invisible plastic pollution could be slowly draining the life out of your favorite leafy friends? Microplastics are exactly what they sound like, microscopic plastic particles less than 5 millimeters in size (smaller than the width of a human hair or a grain of salt). It turns out the same microplastics that pollute our oceans and food are also finding their way into gardens, flowerpots, and farms. And they’re having a surprising effect on how well plants can grow.

New Study Finds Microplastics Are Slowing Down Photosynthesis

A new peer-reviewed study published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), has revealed a global problem that might be happening right in your backyard. A team of international researchers looked at more than 3,200 data points from 157 different studies and found that microplastics can reduce photosynthesis in plants and algae.

Photosynthesis is how plants use sunlight to grow, and microplastics are getting in the way. In some cases, plants lose up to 17 percent of their chlorophyll, which is the green pigment that helps them turn sunlight into energy. Without enough chlorophyll, plants can’t make the food they need to grow, thrive, or produce fruit.

The Data (Explained)

The graph below uses raincloud plots to show how microplastics affect photosynthesis in land plants, marine algae, and freshwater algae. Looking at the color shapes, almost all are to the left of the central zero line, meaning photosynthesis has dropped. The researchers found consistent declines in both photosynthesis and chlorophyll levels, all key indicators of plant health.

Figure 2: Effect sizes on photosynthesis following microplastic exposure for (A) terrestrial plants; (B) marine algae; (C) freshwater algae (Zhu et al. 2025) https://doi.org/10.1073/pnas.2423957122

How Can We Be Sure It’s the Microplastics?

The research team didn’t just compare plants with and without plastic exposure; they used two complementary methods to strengthen their findings. First, they conducted a large-scale meta-analysis, combining results from 157 studies involving over 3,200 observations to assess how microplastics affected photosynthesis across different environments. Then, to validate the data, they built a machine learning model that predicted the impact of microplastics on photosynthesis using real-world pollution levels from terrestrial, marine, and freshwater ecosystems.

Both approaches showed the same thing. When plants, especially smaller and weathered ones, were exposed to more microplastics, they had lower photosynthesis rates. The researchers also looked at specific variables like plastic size, plastic exposure time, and the amount of plastic present. These were the most important factors out of the variables analyzed, (not location or climate) confirming that it wasn’t just random or caused by something else in the environment.

Figure 3: Comparisons of effect sizes obtained from the machine learning model and the meta-analysis (Zhu et al. 2025) https://doi.org/10.1073/pnas.2423957122

What This Means for Your Plants and Your Plate

If your houseplants seem a little sad lately, it might not be because you forgot to water them. Microplastics in your soil, water, or even compost could make it harder for your plants to stay healthy. That includes indoor plants in pots as well as herbs, vegetables, and flowers in garden beds or raised boxes. But the impact goes far beyond your basil or bonsai. Globally, the researchers estimate that microplastics are reducing crop yields by as much as 360 million metric tons every year, including important food staples like rice, wheat, and maize.

Figure 4: The maps on the display the median value of the predicted annual production losses due to microplastic pollution, while the floating bar charts on the right illustrate the range of annual losses for the corresponding crop (Zhu et al. 2025) https://doi.org/10.1073/pnas.2423957122

How You Can Help

You may not be able to remove microplastics from your soil, but you can help prevent more from getting there. Start by refusing single-use plastic items like disposable bags, bottles, and cosmetics that contain microbeads. If you want to stop microplastic pollution at their #1 source, the laundry, CLEANR’s Premium Microplastic Filter for washing machines captures 90%+ of microplastics from the largest source of microplastic pollution, preventing them from entering our environment.

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CLEANR’s Premium Microplastic Filter for washing machines captures 90%+ of microplastics from the largest source of microplastic pollution, preventing them from entering our environment.

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CLEANR builds best-in-class microplastic filters for washing machines that effortlessly remove the largest source of microplastics into the environment. Its technology, VORTX, represents a breakthrough in filtration, with a patent-pending design that is inspired by nature and proven to outperform conventional filtration technologies by over 300%. The company is building a platform filter technology that enables product manufacturers and business customers to materially reduce their microplastic emissions from impacted in-bound and out-bound fluid streams, including residential and commercial washing machine wastewater, in-home water systems, wastewater treatment, textile manufacturing effluents, industrial wastewater, and other sources. www.cleanr.life

Sources:

Zhu, R., Zhang, Z., Zhang, N., Zhong, H., Zhou, F., Zhang, X., Liu, C., Huang, Y., Yuan, Y., Wang, Y., Li, C., Shi, H., Rillig, M. C., Dang, F., Ren, H., Zhang, Y., & Xing, B. (2025). A global estimate of multiecosystem photosynthesis losses under microplastic pollution. Proceedings of the National Academy of Sciences, 122(11), e2423957122. https://doi.org/10.1073/pnas.2423957122