Ask Pablo: Am I An Eco-Hypocrite For Using Roundup To Control Weeds?


Image Source: Will Fuller
Dear Pablo: Am I an eco-hypocrite for using Roundup to control weeds? Are there any good alternatives?

My answer might surprise you, but the most commonly used herbicidal spray, Glyphosate (commonly known as Roundup), may actually not be that bad. After all the bad publicity that we have heard about Roundup, how can this be? What Is Glyphosate and How Does It Work?
Glyphosate is applied to and absorbed by the leaves of a plant. It works by inhibiting the production of a crucial enzyme. Since animals and humans don't have this particular enzyme, the glyphosate is theoretically harmless to us. In fact, the product label states: "This product is considered to be relatively nontoxic to dogs and other domestic animals." Glyphosate has a low toxicity rating from the US EPA but is on the EPA's endocrine disruptor screening list so it is not without its potential dangers, especially with frequent exposure. There has been a lot of testing of the effects of glyphosate on human health as well as toxicity to animals, some of which unfortunately involved having rodents and dogs ingest regular servings of the stuff (According to one source: "No toxic effects were observed in a chronic feeding study with dogs fed up to 500 mg/kg/day, the highest dose tested" but it still doesn't sound very palatable).

When Is Glyphosate Bad?
If the words "Roundup-Ready" strike fear in your heart, you are not alone. For years we have been bombarded by environmentalist groups with scary facts about Roundup and "Frankenfoods," plants that are genetically modified to be resistant to the application of Roundup. Their developer, Monsanto, claims that they "can be used as part of an environmentally responsible weed control program and fit with the vision of sustainable agriculture and environmental protection." So where's the problem? Just as the overuse of "antibacterial" soap has bred super-strains like MRSA, Roundup seems to be creating Roundup-resistant weeds either through cross-pollination with Roundup-Ready crops or natural selection / survival of the fittest. As these weeds spread they will require more and stronger (more toxic) herbicides to keep them under control. Of course the occasional backyard application is not at risk of contributing to this problem, rather it is the large-scale industrial monoculture that we should be concerned about.

What Else Is In That Spray?
Many of the commonly used chemical additives in Roundup actually have more toxicity or environmental consequences than the glyphosate itself. One of the most common additives is a surfactant, essentially a soap that allows the glyphosate to stick to the leaves rather than dripping off. Similar substances, called chemical dispersants, are currently being used in the Gulf of Mexico on the BP oil spill. When used near sensitive aquatic habitats, the surfactants will cause the glyphosate to spread across the surface, posing a serious risk to aquatic life, which is more sensitive to glyphosate exposure. Special formulations of "fish-friendly" glyphosate are available for use near water.

Are There Any Alternatives?
Unfortunately, there is no TreeHugger-approved alternative to glyphosate in terms of its ability to act systemically and kill plants' leaves and roots. Vinegar can be used, with limited success, to kill plants. Vinegar mainly kills leaves as well as temporarily acidifying the immediate area around the plant. All but the youngest plants will re-emerge, requiring successive application. Of course, the least harmful alternatives would be:

  • letting the weeds grow, which will provide habitat for wildlife but won't go over well with the neighbors; or
  • continuously removing weeds by hand, to the detriment of your back.
Of course there are many more options, none of them as effective as Glyphosate, that may be appropriate for your needs. These include covering the weeds with black plastic or tar paper for an extended period of time, letting the sun bake them, their roots, and even their seeds. If you must spray your weeds be sure to allow enough drying time before the next rain, do not over-apply, do not use it near bodies of water unless you have the fish-friendly version and absolutely have to, and don't use when it is windy.

Pablo Päster is a weekly columnist for, an experienced greenhouse gas engineer and the Senior Environmental Program Manager at Hara Software. Send your questions to Pablo(at) or submit the via this form and connect to his RSS feed.
More TreeHugger Articles On Glyphosate:
How Glyphosate Resistance Helps The Organic Movement
GE Crops Provide Short-Term Gain to U.S. Farmers But Long-Term Sustainability in Doubt, Says Report

Genetically Engineered Agriculture Results in Increased Herbicide Usage; Weed Resistance, Farming Costs and Health Concerns on the Rise

Ask Pablo: Am I An Eco-Hypocrite For Using Roundup To Control Weeds?
My answer might surprise you, but the most commonly used herbicidal spray, Glyphosate (commonly known as Roundup), may

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