Outdoor marijuana and hemp growers have long relied on plastic to pot plants, build trellises and tamp down weeds.
Now some of them are looking for ways to reduce their plastic dependency.
Plastic is everywhere, and not only is it bad for the environment, but it also affects human health and food security – and agricultural production is one of the biggest culprits and offenders.
So says a new report – by the United Nations Food and Agriculture Organization, an agency that promotes food security and sustainability – that details how plastic pollution has become pervasive in agricultural soils.
The U.N. warns that land used to grow food and other consumer products is contaminated with large quantities of plastic pollutants, including microplastics, to an even higher level than the oceans are.
Marijuana and hemp are often grown on raised beds covered with plastic to block sunlight from hitting the ground and to stimulate weed growth.
The practice also warms the earth to help seeds germinate and young plants get established quickly, increasing yield and season length.
Unlike other crops that need new plastic each season, cannabis does not, and producers are finding they can leave the plastic in place after harvest.
Even though that saves on waste, chemicals from the plastic could be leaching into the soil, said Brandon Rivers, founder and president of San Luis Obispo, California-based SLO Hemp Co.
“That material is sitting directly on the bedded rows, it’s being exposed to ultraviolet light and moisture and it’s degrading just from natural oxidation,” he said.
Rivers added that instead of plasticulture, many California cannabis producers are using hay and straw, or plant-based biodegradable mulch film to cover outdoor bed rows and block sunlight to weeds. Such methods also hold in moisture and reduce water waste.