Ditch the Plastic Mulch — The Lowdown on Earth-Friendly Alternatives


Landfill-clogging plastic is widespread in our daily lives, from our sunglasses to our shampoo bottles—but I didn’t realize until a few weeks ago that it could be in our gardens and farms, too.

Standard black mulch—which tamps down on weeds and stimulates plant growth—contains petroleum-based plastic that doesn’t break down easily.

That’s why researchers at Washington State University’s Mount Vernon Northwest Washington Research & Extension Center are getting their hands dirty figuring out whether biodegradable mulches can work as well as plastic mulches.

I visited the center—situated in the fertile Skagit Delta, about an hour from Seattle—not long after its researchers received a grant from the U.S. Department of Agriculture to investigate the much-debated mulch question.

But first, a bit of background: Since its introduction in the 1950s, harvest-boosting black mulch has been a favorite of U.S. farmers. By 2006, up to 400,000 acres of U.S. farmland were blanketed with the stuff, according to the Web site of another WSU facility, the Vancouver Research and Extension Unit.

In fact, there’s even a catchy name for using plastic in farming: plasticulture.

Unfortunately, after harvesting mulched crops, many farmers choose to dispose of the waste in landfills, according to WSU.

Yet many small-scale and organic farmers have resisted going plastic, opting for degradable mulches that have been available since the 1980s. (Also, black mulches don’t meet National Organic Program qualifications.)

The Vancouver unit has done a series of studies on whether these alternatives are in the same caliber as their plastic counterparts.

For instance, they’ve tested paper mulches, cornstarch-based mulches, and even plastic mulches that degrade in fewer than 145 days.

The unit’s 2007 report found that black mulches were still supreme, but one type of paper mulch was as durable as the plastic kind—at least in the first year.

While WSU researchers and colleagues dig deeper into the merits of eco-mulch in coming months, in the meantime you can try some alternatives yourself.

A quick Web search turned up this this paper mulch called Planters Paper, for instance, as well as a cornstarch-based mulch, BioTelo.

And lastly, some of you who submitted to Green Effect have already been thinking up some creative landfill work-arounds. For instance, the “Green Team” at Paul Ecke Central School near San Diego, California, has piloted several composting and recycling initiatives involving at least 25,000 elementary school students. The school also hosts a weekly farmer’s market.

So keep on tillin’!

–Christine Dell’Amore

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–“Green” your lawn with these organic lawn care tips.

–Check out our fertilizer buying guide.

–Get the dirt on compulsory composting.

Photograph courtesy Carol Miles/Washington State University

Human Journey

Meet the Author
Christine Dell'Amore, environment writer/editor for National Geographic News, has reported from six continents, including Antarctica. She has also written for Smithsonian magazine and the Washington Post. Christine holds a masters degree in journalism with a specialty in environmental reporting from the University of Colorado at Boulder. Her book, South Pole, was published in 2012.