Microplastics in the Garden: What You Need to Know

Plastic has crept into every aspect of our lives, and gardens are no exception: pots and planters, nets, tarps, watering cans… even artificial plants! In its early days, it had everything going for it: it was inexpensive, lightweight, durable, and easy to mold to our needs. But today, we realize that this “miracle” also hides risks far greater than we could have imagined. Not only does it generate waste that is difficult to manage, but it also breaks down into microplastics that contaminate the soil, water, and, inevitably, our gardens. And what about our vegetable gardens? What happens to our food?

What Is Microplastic?

Microplastics are tiny plastic particles measuring less than 5 millimeters, which come either from the slow degradation of larger objects (bags, bottles, synthetic clothing, etc.) or from direct manufacturing in small sizes, such as the microbeads once used in certain personal care products. Invisible or almost invisible, they are now found everywhere: in the air we breathe, the water we drink, the soil, the oceans, and even in living organisms. Because they persist in the environment for a very long time and can be ingested by humans, microplastics are causing growing concern about their effects on the health of ecosystems and our own health.

How Does Plastic End Up in the Garden?

Obviously, any plastic object left in the garden will eventually degrade over time under the effects of sunlight and frost. But microplastics also find their way into the garden through soil, compost, manure, soil amendments, and fertilizers, which may already contain them—often because they have been stored in plastic containers. They also travel through the air, carried by wind and rain, or even by watering. Even if we make efforts to limit plastic in the garden, these tiny fragments, already ubiquitous in the environment, inevitably end up accumulating in the soil of our vegetable gardens and flower beds.

To gain a clearer understanding, let’s examine their impact from three angles: soil, wildlife and the microbiome, and plant health.

Soil

The foundation of any garden is the soil. It is through the soil that plant roots draw the water, air, and minerals necessary for their development. However, the presence of microplastics disrupts this process. A recent study has shown that they weaken the soil structure. Normally, healthy soil forms large, stable aggregates—small blocks that allow air and water to circulate properly. With the addition of microplastics, these aggregates decrease and break down into smaller, unstable particles, and the soil becomes less cohesive, less permeable, and therefore less effective at retaining the water, air, and nutrients that plants need.

Added to this is another problem: plastics not only release fragments, they also release chemical additives such as phthalates, bisphenol, and certain heavy metals. These substances, which are incorporated into plastic to give it flexibility, color, or strength, gradually escape as the plastic ages and accumulate in the soil.

Other studies, however, qualify this picture: while some additives are harmful to soil health, plastic particles themselves can sometimes increase porosity and facilitate root growth, particularly in the presence of plants. In short, microplastics are not neutral. The majority of studies suggest that they weaken soil structure and stability, but certain specific effects (such as improved aeration) may occur under particular conditions.

Fauna and Microbiome

We now know how essential soil fauna and microorganisms are to plant health. The living organisms found in soil help make nutrients available for plants, work with roots to improve their efficiency, and contribute to the formation of a more stable and fertile soil structure.

The presence of microplastics in their environment also affects these little allies in the garden. A 2024 study exposed different species of earthworms to microplastics, resulting in internal inflammation, oxidative stress, reduced respiration, and even damage to digestive tissues. This affects their metabolism, survival, and of course their benefits to the garden.

Microplastics also disrupt mycorrhizal fungi, which help plants better absorb water and nutrients. They can exacerbate the harmful effects of heavy metals on these plant-fungus associations, thereby reducing their essential role in plant health and growth.

Bacteria are also affected by these small plastic particles, which reduce the diversity of beneficial species that contribute to soil fertility, such as those that fix nitrogen or make phosphorus available to plants. This disrupts natural nutrient and carbon cycles. In addition, plastic particles colonized by microbes harbor impoverished biodiversity, dominated by opportunistic species, further reducing the microbial richness of the soil.

Plant Health

Pendant longtemps, on pensait que les microplastiques restaient uniquement dans le sol ou étaient ingérés par les animaux. Mais depuis quelques années, plusieurs études ont confirmé que les plantes peuvent les absorber.

Nanoplastics, which are even smaller than microplastics, are particularly concerning because their size allows them to easily penetrate plant roots and circulate to stems, leaves, and sometimes even fruit. Once inside, they cause oxidative stress that damages cells, reduces germination and growth, and can impair photosynthesis. In addition, these tiny particles act like sponges for pollutants, transporting heavy metals or pesticides directly into plant tissues.

Risks to Human Health

Can microplastics from our gardens end up on our plates? Yes. Is this a cause for concern? Yes, of course, but no more so than their already ubiquitous presence in our homes, our environment, and even the food we buy in stores.

I can’t give you precise information about the presence of plastics in our garden crops, but one thing is certain: microplastics represent an emerging risk to human health. Ingested with water or food, or inhaled through the air and dust, they can cause inflammation and oxidative stress in the body. Some also release toxic additives known to disrupt the hormonal system. Although their long-term effects are still poorly understood, we already know that they accumulate in our tissues and contribute to our overall exposure to plastic pollution.

Is eliminating plastic in the garden a lost cause?

Completely eliminating plastic from the garden is undoubtedly unrealistic: it is already ubiquitous in our environment, and our gardens are no exception. But that doesn’t mean that all efforts are in vain. Rather than aiming for “zero plastic,” we can reduce plastic use where possible—for example, by replacing synthetic mulch fabrics with organic mulch, or by choosing terracotta, wood, or metal pots rather than disposable plastic containers. As for solid, reusable plastics, it’s best to keep them for as long as possible to limit the production of new waste. So it’s not an impossible mission, but rather a gradual shift toward more sustainable choices, in the garden and elsewhere.