Week of 04/11/10

Dear EarthTalk: I pruned back an overgrown bush in my back yard last fall and now the soil around it is covered in dandelions and other weeds. Is there any way to get rid of these weeds without resorting to RoundUp and other chemical herbicides?

—Max S., Seattle, WA

Weeds are nothing if not opportunistic. While you may not have bargained for getting one form of eyesore (weeds) by clearing another (an overgrown bush), dandelions and other fast-growing, quickly spreading plants know no bounds when some new territory opens up. They will colonize and spread out given the slightest opening—after all, that’s what defines them as weeds.

Of course, conventional herbicides such as Monsanto’s RoundUp will take down the weeds in a jiffy, but the negative effects on people, animals and the environment may be both profound and long-lasting. Independent studies of RoundUp have implicated its primary ingredient, glyphosphate, as well as some of its "inert" ingredients, in liver damage, reproductive disorders and Non-Hodgkin’s Lymphoma, as well as in cardiovascular, gastrointestinal, nerve and respiratory damage.

California’s Department of Pesticide Regulation reports that, year after year, RoundUp is the number one cause of pesticide/herbicide-induced illness and injury around that state. RoundUp is also blamed for poisoning groundwater across the U.S. and beyond, as well as for contributing to a 70 percent decrease in amphibian biodiversity and a 90 percent decrease in tadpole numbers in regions where it is used heavily.

No doubt, the most eco-friendly way to get rid of weeds is to yank them out without the aid of poisons.© Lastonien, courtesy Flickr

Given that you"ll have to manually remove dead weeds from your yard after applying RoundUp (or any other "post-emergent" herbicide), why not just pull them up by hand in the first place? No doubt, the most eco-friendly way to get rid of weeds is to yank them out without the aid of poisons. Unfortunately, many weeds have long deep roots which need to be pulled completely if you don’t want them to grow back; if need be, use a metal weed puller with a hooked end or a mechanical grabber—available at any local garden supply or hardware store—if you don’t want to have to pull those very same weeds next year.

Garden expert Dean Novosat of the Garden Doctor website suggests giving the weed beds a good watering the night before you pull weeds. "
the soil will be softened and will yield the entire weed plant, root and all," he says. Another way to kill weeds, he says, is by pouring boiling hot water over them.

Of course, once you’ve killed or pulled up all those weeds—and make sure you’re thorough or else it’s waste of time—you"ll want to make sure new ones don’t start showing up in their place. Planting some regionally appropriate and ideally native plants in place of the removed weeds would be a good first step—check with a local nursery about what some good choices might be for your neck of the woods.

Once the area is cleared (and replanted), cover it with three to six inches of mulch. Mulch forms a barrier between the soil and the sun, depriving any new germinating weeds of the sunlight they need to photosynthesize. Mulch is composed of large chunky material such as wood chips and bark nuggets, and works well for weed control also because it is low in nutrients and thus won’t fertilize plant starts below.

CONTACTS: California Department of Pesticide Regulation; The Garden Doctor.

Dear EarthTalk: How effective have plastic bag bans and restrictions been on reducing plastic litter and other problems associated with their proliferation? And is it really better to use paper bags, which will just lead to more deforestation?

—Peter Lindsey, New Canaan, CT

Americans go through some 92 billion disposable plastic bags each year.© Kate Ter Haar, courtesy Flickr

Plastic bags, first introduced in the 1950s as a convenient way to store food, have since developed into a global scourge, littering roadsides, clogging sewer drains and landfills and getting ingested by animals and marine life. And in recent years we’ve discovered how they are so prolific that they now comprise a significant portion of the plastic and other garbage that has collected in huge ocean gyres far from land.

A few countries around the world—Bangladesh, China, India, Australia, Greece, Ireland, Italy, Israel, South Africa, Taiwan and Mumbai, among others—have taken stands against plastic bags through taxing their usage or banning them outright. The environmental think tank, Worldwatch Institute, reports that China’s decision to ban free plastic bags in 2008 has cut demand by some 40 billion bags, reduced plastic bag usage there by 66 percent, and saved some 1.6 million tons of petroleum.

In March 2007, San Francisco became the first (and is still the only) major U.S. city to implement an across-the-board ban on plastic bags. Large supermarkets and pharmacies there had to ditch plastic shopping bags by early 2008 in favor of paper bags or those made from all-natural biodegradable cornstarch-based plastic. Environmentalists are particularly fond of the latter option for those who don’t bring their own grocery bags, as these cornstarch bags offer the biodegradability of paper without the deforestation as well as the convenience of plastic without the damage to ecosystems. San Francisco officials had originally tried to work with retailers on reducing plastic bag use voluntarily. But after a few years of little or no cooperation, they decided to just institute the ban on anything but biodegradable bags. The result has been a 50 percent drop in plastic bag litter on the streets since the ban took effect.

Los Angeles followed suit and its city council voted in 2008 to ban plastic bags beginning in July 2010—but the ban will only take effect if the state of California doesn’t follow through on a statewide plan to impose a fee on shoppers who request plastic bags. City council members in L.A. hope the ban will spur consumers to carry their own reusable bags and thus reduce the amount of plastic washing into the city’s storm drains and into the Pacific Ocean. Several other U.S. cities, including New York, Philadelphia and Baltimore, have considered outright bans like San Francisco"s, but each settled instead on plastic bag recycling programs in the face of pressure from the plastics industry and retail commercial interests.

While increased demand for paper bags in the wake of plastic bag bans could lead to more deforestation, most paper grocery bags in use today are made from recycled content, not virgin wood. Also, an added benefit of paper over petroleum-based plastic is its biodegradability.

Americans go through some 92 billion disposable plastic bags each year, and only five billion paper ones. If the nation banned plastic bags it is likely that paper varieties would only make up a small part of the difference, in light of the proliferation of reusable canvas shopping bags as well as the availability of biodegradable cornstarch plastic.

CONTACT: Worldwatch Institute.

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