Alternatives to Roundup

The widespread use of the herbicide Roundup has raised significant health concerns. The core of these concerns centers on glyphosate, Roundup’s active ingredient, and its link to cancer.

Research on Roundup and cancer published in the journal Mutation Research showed a 41% increased risk of non-Hodgkin lymphoma in agricultural workers exposed to large amounts of glyphosate. Researchers have also associated glyphosate with other forms of cancer, oxidative stress and increased estrogenic activity in breast tissue cancer cells. Despite these findings, Roundup remains a popular choice, partly due to its effectiveness.

“There’s a reason that glyphosate is still in use despite the health concerns about it,” Ryan Farley, co-founder and CEO of LawnStarter, told Drugwatch. “It’s a highly effective weed killer that doesn’t affect Roundup Ready crops, meaning that you can spray it all over a field and only kill the plants you don’t want.”

Warning labels on Roundup products do not inform consumers of these risks, and the U.S. Environmental Protection Agency in 2020 initially found no human health risks with glyphosate, Roundup’s active ingredient. The EPA is currently reassessing glyphosate’s status as a human health concern and environmental contaminant. This ongoing situation has led to confusion among consumers, sparking over 100,000 Roundup lawsuits against Bayer, the manufacturer of Roundup, and leading them to search for safer alternatives.

Natural Roundup alternatives don’t contain glyphosate. Instead, they use soap, vinegar, salt combinations, corn gluten meal and iron-based herbicides to kill weeds. Some contain acetic acid — the component that gives vinegar its characteristic odor — which damages the leaf cuticle and causes cell leakage to kill weeds rapidly. Manual weed control methods like mulching and pouring boiling water over adult plants can also deter growth.

These safe alternatives to Roundup can be effective if used properly. But alternatives may also require more work.

“Especially on an industrial scale, all of the alternatives are either much more labor-intensive or much less targeted,” Farley said. “You can get out there and pull the weeds by hand or you can use herbicides that will also damage your crops.”

It may be more labor intensive and tedious, Chrissie Handley, a lawn care specialist at Online Turf, told Drugwatch. But she says alternatives can be worth the extra work in the long run.

“Prevention is always key and is your strongest battle against weeds when it comes to getting the best use out of your eco-friendly weed killer alternatives,” Handley said. “You also may have to re-apply and be more persistent with the eco-friendly solutions to get the full effect.”

Acid-Based Herbicides

Vinegar is a safe Roundup alternative that damages weeds by causing leakage within leaf cells. Although more concentrated formulas are available, vinegar is typically 4% to 6% acetic acid.

“Vinegar’s acidity dries out the surrounding area, shutting off moisture absorption to the plant and killing it,” Handley said. “But it will also affect surrounding plants, so it’s best to use it in a targeted manner.”

Even so, vinegar may not kill the roots of a plant and multiple applications may be needed to slow plant growth.

Acetic acid concentration and plant age are important factors to consider when choosing an acid-based herbicide. Scientists from the USDA Agricultural Research Service found that 5% to 10% concentrations of acetic acid successfully killed weeds in their first two weeks of life, while higher concentrations are required to kill all plant stages faster.

Corn Gluten

Though ineffective in heavy rain and expensive compared to other natural substitutes, original studies on corn gluten as a natural herbicide found that it could successfully eliminate germinating seeds. 

However, conflicting findings in a two-year study by researchers at Oregon State University showed corn gluten to be completely ineffective in controlling weeds. Corn gluten, they found, even increased grass and weed growth because of its high nitrogen content. And, according to researchers at the University of Maryland, the amount of corn gluten required for effective weed management may violate certain state environmental laws.

Essential Oils

Essential oils are effective organic herbicides since they can damage plant tissue and inhibit growth. Essential oils can kill weeds through multiple means: by causing cell death, reducing energy intake and altering enzyme and hormone regulation.

Examples of active ingredients in essential oil-based herbicides include cinnamon, clove and red thyme. They pose minimal environmental risks and are less likely to leave residue in water or soil.

While essential oil-based herbicides can kill weeds, they can also increase the risk of skin cancer and cause skin irritation, according to a 2021 research article published in the International Journal of Molecular Sciences. Inhalation of these oils can also irritate mucous membranes, and ingestion can lead to nausea, vomiting and diarrhea.

Iron-Based Herbicides

Iron-based herbicides effectively dry broadleaf weeds almost immediately after application. The application rate determines their effectiveness, but it shouldn’t be used before heavy rain. They may also cause grass discoloration, especially during hot weather.

Iron-based herbicides have been used since the late 1800s. New plant treatment delivery systems called metal-organic frameworks use iron-based metal-organic frameworks, or MOFs. Iron MOFs carry fungicide treatments into plant tissues effectively. However, they can cause eye or skin irritation and lung irritation if inhaled.

Mulch and Other Manual Approaches

Mulching with natural materials like leaves, pine needles, dried grass clippings or small pieces of wood can suffocate weeds by blocking sunlight. Barrier landscape fabric can also block sunlight, but it can damage the soil structure and leach chemicals.

You can also use groundcover plants to help prevent new weeds from emerging. Pulling weeds up by the roots is effective but time-consuming, while fire can be dangerous and won’t kill the roots underground. The heat from boiling water or steam can even be used to kill weeds.

“[Boiling water is] best used on early-growth weeds to wipe them out before they have grown,” Handley said. “For more advanced weeds, you may need to re-apply.”

Soap Salts

Potassium salts of fatty acids, or soap salts, are the main effective ingredient in many herbicides. People have used soap salt products for decades. The U.S. Food and Drug Administration generally recognizes them as safe for food crops.

“Salt can dehydrate a plant, so it will kill weeds but can harm the soil and surrounding plants if used in excess,” Handley said.

Soap salts can cause skin irritation with prolonged contact and stomach issues if ingested in large amounts. They are highly toxic to certain aquatic species and should not be disposed of in water.

A 2020 study published in Food and Chemical Toxicology found that chemical herbicides that don’t use glyphosate can still be dangerous.

The study tested 14 different chemical herbicides and found that all contained dangerous chemicals not listed on the label. These chemicals ranged from known carcinogens to toxic heavy metals including mercury and arsenic.

Chemical alternatives to Roundup come with other limitations. These products aren’t as effective as Roundup during hot weather, and many only kill small broadleaf weeds but not large plants. As with Roundup, these herbicides should not come into contact with surrounding plants because they aren’t selective and can cause cosmetic damage or kill nearby plants.

Integrated weed management involves using different techniques — or a combination of them — such as preventing weed growth, using tools to remove weeds, using chemicals, changing the way you grow your plants and introducing helpful insects.

By using a combination of these methods, you can help keep your garden or farm healthy and weed-free.

Integrated weed management prevents large-scale weed problems. Controlling weeds around the edges, removing them before they grow large, using clean seed mixes, planting shallowly and rotating herbicides with different active ingredients can all help you keep weeds in check.

Roundup continues to be a popular herbicide. Roundup still generates big profits for Bayer despite studies showing that glyphosate increases the risk of certain cancers and other serious illnesses.

In February 2020, the EPA published the interim decision registration review decision (ID) for glyphosate after considering public comments. The EPA concluded that there are no human health risks with glyphosate when applied following its current label. The EPA also reported glyphosate as “unlikely to be a human carcinogen”. 

The EPA is currently reevaluating its stance on glyphosate as a human health concern and environmental contaminant. In the meantime, consumers remain confused about the negative health impacts of glyphosate, leading to more than 100,000 Roundup lawsuits against Bayer.