At first glance, plastic mulch may be mistaken for warm blankets that both envelop and protect growing plants. But closer inspection reveals that plastic mulch actually bears a better resemblance to garbage bags, thousands of them, fused together into unbroken strips.
Growers are increasingly relying on “plasticulture”—or plastics in agriculture—to control weeds, conserve moisture and regulate soil temperature. Some farmers attest that plastic mulch is necessary to optimize growth for crops including strawberries, tomatoes, lettuce and celery.
But others remain wary. Critics warn that plastic mulch produces copious amounts of plastic waste that linger in the environment for generations. Mounting evidence suggests the critics are right.
Why use plastic to cover crops?
Each year, the U.S. agriculture sector alone uses 126 million pounds of plastic mulch annually. In California, plastic mulch helps farmers grow more than a quarter of the state’s fresh fruits and vegetables.
For farmers, the product is certainly appealing. Plastic mulch adds heat to the soil and is especially beneficial for heat-loving crops like strawberries. It retains fertilizer, too, by reducing leaching and promoting efficient nutrient management. And because plastic mulch reduces soil evaporation and thus conserves water, it is especially beneficial in drought-prone areas. Even some organic farmers have embraced plastic mulch for suppressing weeds without synthetic chemicals.
Does using plastic to cover crops hurt the environment?
Although advocates argue that plastic mulch increases yields by up to 30%, a growing body of research suggests that reliance on plastic mulch creates unnecessary plastic waste.
Plastic mulch is not easily recycled. Although technically recyclable, plastic mulch is rarely recycled. That’s because recycling plastic is generally only possible if contaminants make up less than 5% of the weight of plastic mulch. But by the end of the growing season, plastic mulch’s weight can increase by as much as 80% thanks to surface dirt and organic matter. And because there are no consistently accessible mechanisms for sustainably disposing of plastic mulch at the end of its life, the vast majority heads to the landfill, is incinerated or remains in the environment as plastic pollution.
The remnants that linger become plastic pollution. Macroplastics form when long-term use of plastic mulch results in plastic particles breaking off and migrating into deeper layers of the soil. Plastic that’s enmeshed into subsoil is difficult—if not impossible—to remove and may remain for centuries. One study suggests that such macroplastics damage soil structure and stunt plant development.
Plastic mulch breaks down into microplastics, too, when it weathers to such an extent that tiny plastic particles form. Microplastic pollution is already widespread and presents potential harms to wildlife and marine life. A growing body of scientific evidence suggests that microplastics are toxic to human health.
Plastic mulch contributes to our growing plastic waste problems
Plastic mulch may be convenient, but it’s creating even more plastic waste. And the last thing we need is more plastic pollution.
Plastic takes centuries to break down, which means that today’s plastic mulch, plastic bags and plastic bottles will litter our streets and pollute our oceans for generations. If you’re looking to cover rows between crops or garden beds, organic mulches may work just as well. Straw mulch suppresses weeds and retains soil moisture without pesky plastic. Shredded bark and woodchips, too, decompose slowly and provide longer-lasting benefits.
Environment America is addressing plastic pollution by urging plastic producers and major corporations like Trader Joe’s, Whole Foods and Pepsi to do their part to reduce the amount of plastic that ends up in our environment.
Before you go: Urge Pepsi CEO Ramon Laguarta to commit to meaningful plastic reduction.
