When it comes to weed control, Roundup is a household name. The main ingredient in Roundup, glyphosate, is among the most popular — and most effective — herbicides on the market. It also has become one of the most controversial.

A federal glyphosate lawsuit filed on behalf of 11,200 plaintiffs against chemical manufacturer Bayer AG alleges that Roundup causes cancer (and new research exploring the links between glyphosate and cancer found that exposure to the ubiquitous weed killer was associated with a 41 percent increase in cancer risk).  In March 2019, a jury found Roundup was a substantial factor in the cancer of a California man and ordered Bayer pay $80 million.

Some local government agencies have either suspended its use on public land or embarked on studies to assess its use.  Environmental groups such as Beyond Pesticides are organizing campaigns to urge statewide bans. “It is time to stop glyphosate use or risk continued exposure to the state’s populations and adverse health effects, along with the financial exposure that the threat of litigation brings,” a Beyond Pesticides release says.

Yet the chemical has firm support among U.S. regulators, including the U.S. Environmental Protection Agency. The EPA on April 30 released its latest findings, which reaffirmed that the agency considers glyphosate no risk to public health.

As the debate rages on, we look at the pros and cons of using glyphosate on your lawn and garden.

Dr. Joel Neal
Dr. Joel Neal

Pros of Using Glyphosate

Roundup works: One shot of the powerful chemical is enough to make weeds wither. In fact, Dr. Joe Neal, professor of weed science at North Carolina State University, believes that without glyphosate-based herbicides like Roundup, creeping perennial weeds like mugwort and Bermudagrass will be more difficult to control. “The currently available alternatives to glyphosate are less effective and more expensive to use,” he says.

It increases farm yields: On large-scale agricultural applications, glyphosate increases the size of harvests by killing off weeds that would otherwise compete with crop plants for water and nutrients.

Chip Bubl
Chip Bubl

The results are immediate: If your goal is to kill weeds popping up in the sidewalk cracks, decimate invasive plants or renovate the lawn without peeling back the sod or tilling it under, Roundup works fast. The weeds will die almost immediately and you can overseed the lawn in as little as 48 to 72 hours after application, according to Chip Bubl, Oregon State University extension agent.

Cons of Using Glyphosate

It might work too well: Roundup is considered a “nonselective” herbicide, which means it kills all foliage that it comes in contact with. If you’re not careful when you’re applying glyphosate-based herbicides, you could end up killing more than Bermudagrass and dandelions: Parts of the lawn and your favorite garden flowers could die, too. Neal’s advice: Be careful not to go spray any desirable plants.

It could harm the environment: Although glyphosate binds to the soil and is considered to have limited potential for runoff into surface waters, studies have shown that even at low doses, the herbicide stimulates the growth of toxic algae and could affect both wildlife and livestock.

Health risks remain unclear

Neal notes that glyphosate was long considered one of the least toxic and environmentally benign herbicides on the market and that the largest study done concluded it is safe and poses no increased cancer risk. Few studies have explored the connection between Roundup and other diseases but one review highlights possible links to cancer, kidney disease and impaired reproductive development.

Glyphosate alternatives

Glyphosate is ubiquitous. In addition to Roundup, the National Pesticide Information Center estimates that the herbicide is an active ingredient in more than 750 lawn and garden products sold in the U.S. A powerful chemical might be overkill when it comes to certain weeds. Annual broadleaf weeds such as chickweed, dandelion and spurge can be well-controlled with alternative methods (perennial weeds and grasses are harder to control).

You could instead:

  • Pull out the weeds by hand.
  • Apply natural weed killers. Vinegar is overrated, but there are plenty of other, effective organic herbicides.
  • Use flame weeders (where no flammable materials are present).
  • Use pre-emergent weed killers designed to keep annual weeds from germinating.
Roundup by Monsanto: an effective, but now controversial weed-killer
Roundup in use: It’s a nonselective plant-killer, so to be effective in a lawn it must be sprayed precisely.

Glyphosate safety tips

If you decide to use Roundup or other similar products, remember glyphosate’s power and take precautions. Neal suggests:

  • Wear long sleeves, long pants and gloves.
  • Avoid all direct exposure between the chemical and your skin.
  • Don’t spray on windy days and watch your overspray.
  • Keep people and pets off the treated areas until the spray has dried.

“Limit the exposure, limit the risk,” he says.

Before using any herbicide, including Roundup, Bubl advocates reading the label. If the microscript on the bottle is too small to decipher, look it up online.

“You should be knowledgeable about what you’re using,” he says.

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