A Down-to-Earth Guide to Understanding and Using Glyphosate

Glyphosate is what chemists call an organophosate. It is made up of the elements carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and phosphorus (P) in the ratios C₃H₈NO₅P. So far, it is only known to be produced by humans creating a chemical reaction, which results in a colorless and odorless crystal. It is most well known for being the main ingredient of certain herbicides, the most well known brand name being Roundup™. It was first sold in the early 1970′s, which means people have been using it for a solid 40 years.

The big question on a lot of people’s minds is whether or not it is safe to use glyphosate. Some people claim it is toxic. Other’s say it is quite safe. There are studies that are cited to bolster all conclusions. How can the average person know whom to believe?

Thinking through some vocabulary can help. What do the words “toxic” and “safe” mean? Many substances can be both toxic and safe, depending on amounts and circumstances. A classic example is table salt. Salt is not only safe in certain concentrations, but necessary for life – unless, of course, it is used in amounts or situations where it is toxic. A toxic amount to ingest or absorb cannot be strictly defined for each individual. Factors including climate and activity level can make a big difference.

You might be thinking the comparison doesn’t matter because we don’t need any glyphosate in our bodies or the environment. That, however, would be a rather sweeping statement. While I am not advocating ingesting substances willy-nilly, there are many things about our bodies and the earth that we do not know, have not measured, or constantly find are misunderstood. It should come as no surprise that no one has previously thought to go around measuring chemicals that we were not aware could exist. And just because the first known instance of a chemical (in our recollection) was due to manufacture, it does not mean it didn’t or doesn’t already exist in forms somehow beyond our current radar. This is not nitpicky. This is the reality of the limitations of science, which can never 100 percent prove anything.

I remember learning in nursing school, while doing a research report on breast milk versus formula, that for a while doctors were recommending supplements to breastfed babies because scientists could not find any Vitamin D in breast milk. Somewhere along the way, they found a precursor to Vitamin D in the mother’s milk that the baby’s body used to synthesize Vitamin D. The point is that research is very limited by what people expect to find.

Speaking of synthesizing things – you have to love that word. It is right up there with “toxic” when it comes to derogatory labels. Such rhetoric is misleading, though. It is not like people can whip up these things out of nothing. Everything is made from the building blocks we find in the world around us, harnessing natural processes. Our human creativity is limited by what we have been supplied with. At what point do we cross over from “natural” to “synthetic.” Not only that, but is “natural” always the better choice? What if it is more destructive to the environment to obtain it? What if it is more costly, so that fewer people can reap the benefits? What if it is more harmful overall? Or what if not nearly as much is known about the effect? These are real issues with many substances categorized as natural.

Synthetic chemicals -0h, wait. Chemical is another often misunderstood word. This would be a good time to recall that chemicals are what everything is made out of, “natural” or “synthetic.” Chemistry is simply the study of trying to understand and use resources on a molecular level. Obviously, not everyone agrees about the best way to use this knowledge. Discussion is generally helpful, because “two heads are better than one.” But to demonize any substance because it is a “chemical” is probably due to lack of understanding or using the term for emotional impact.

The chemicals that tend to get made are those considered to be of value. Someone somewhere envisions a use for them. If enough people choose to buy them, there is incentive to produce more of them. If the chemicals or an effective option to them were known or allowed to be found readily, at a decent cost, out in the wild, it is unlikely that anyone would be trying to come up with a particular substance in the lab.

Plants are made of chemicals. They synthesize quite a few substances, some of which we like. Some of the plants are drop-dead poisonous. Other plants are threatening the “natural” ecological status quo with their prolific growth habits. There are even plant parts that we eat regularly that have “natural” “toxins” in them, but we eat them anyway. Almost anything is “toxic” if eaten exclusively or in extraordinarily high amounts for an extended period of time. We manage plants to provide for our needs and care for our property. There are times when the best option is to kill plants. This could be as benign as thinning your carrots for a better harvest or as stressful as trying to eradicate the stand of water hemlock growing in your irrigation ditch so that small children don’t die from using the stems as blow guns. At some point, an herbicide can be useful.

The glyphosate based herbicides are actually made by converting the glyphosate to a salt, so that it will dissolve in water. Frequently, there are a few other things added. Although these additives are not considered “active” ingredients, they are there for a reason and affect how the glyphosate works. One of the main additives is usually a soap-like substance, such as is normal in household products. Called “surfactants,” these help the herbicide be effective by breaking down waxy or fatty barriers in the plant leaves. It is these additives that tend to irritate the skin and eyes, if they are bothered. They are also what makes the herbicide dangerous for aquatic life. If the surfactants are not added, the frogs seem to be fine. It is worth noting that vinegar, something frequently suggested as a substitute for glyphosate, is also harmful to frogs.

The glyphosate herbicide works by blocking the plant’s ability to perform vital functions. Specifically, an enzyme action is interfered with so that the plant cannot use it’s metabolic mechanisms to synthesize amino acids it needs to grow. This particular metabolic function is unique to plants, fungi, and bacteria. Humans and animals don’t use it. (click on any photo to enlarge)

A dead weed in one of my garden pathways a couple of weeks after being sprayed with glyphosate.

Glyphosate actually doesn’t work against all plants. Just like some plants resist cold and frost, some plants are not much affected by glyphosate ever since it has been around. In the dandelion, for example, the higher levels of iron in the leaves can bind with the glyphosate before it can do systemic damage. This also supports the hypothesis that the mineral content of water used for dilution of concentrates can render the herbicide less effective. Such things could lead to false reports of glyphosate resistance and/or unnecessarily high application rates of the herbicide.

Similar to antibiotic resistance among bacteria, there may also be some of any given plant population that are not as susceptible to the glyphosate. When the weaker plants die, the stronger ones propagate. There are three main ways plants are thought to resist glyphosate:

They produce enzymes that are less likely to bond with glyphosate.
The herbicide is somehow collected in the leaves, instead of getting transported to the whole plant, i.e. the roots.
The genetic code enables the plant to make such a high concentration of the necessary enzyme that the herbicide can’t block them all.

Does this mean glyphosate, or any herbicide, should be avoided in order to avoid resistance? Probably not. At least it is killing weeds for now. Also, not every plant is resistant to every herbicide. There are choices for dealing with infestations not responding to glyphosate (but that is not the subject of this article).

Resistance, according to what I read, seems to be roughly defined as 60 percent failure. Currently, there are 24 plants that appear to be resistant, 14 of which are in North America. Among them are common ragweed, Palmer amaranth, horseweed, kochia, and common water hemp. Plants can also be more or less resistant depending on air temperature, time of day sprayed, and overall sources of water for the plant.

It has never been recommended that herbicides be the only method of weed control for anyone. Hand weeding and mulch can help control many weeds, depending on the size of the area and the type of weed. Unfortunately, some weeds are impossible to get up by the roots, like bindweed and ground cherry. Herbicides can get down to the roots on some of these. Some weeds are too close to desirable plants to efficiently apply herbicide. But every form of weed control has it’s challenges and drawbacks. Mulch can decrease needed airflow to the soil, or need to be constantly attended to near stems to avoid rot or pests. Plastic mulch will heat up the soil enough to kill beneficial insects and soil microbes. Home made or supposed organic remedies often don’t kill roots, have surfactants just as trouble causing, or have to be applied much more frequently at higher cost. As mentioned when talking about frogs, so-called organic methods should not be assumed to be less harmful. If they are working, there is something strong enough in them to get the job done. Common substances like table salt and boron can leave the soil infertile for years. Flaming kills everything in its path and is dangerous during dry seasons.

There are three ways to apply glyphosate herbicides.

Broadcast spraying, where everything in the area gets a dose. This can be the most time effective. In some forest management situations, it is used at a specific time when desirable trees are known to be in a resistant part of their life cycle.
Drilling and pouring, where the herbicide is put right inside a tree stump to kill the roots. Anyone who has ever tried to remove a tree knows how persistent growth from remaining roots can be unless the stump is killed.
Spot spraying, which is basically what most home gardeners do and is a very controlled method of application.

Having verified that the mode of action by which glyphosate kills plants is not one by which it can harm people or animals, it is still reasonable to wonder if it harms us or the environment in other ways. It has certainly been claimed that glyphosate causes everything from autism to cancer. There are reports of finding it in ground water, breast milk, and urine. One study is said to prove it kills human cells. The fact that people applying it are advised to wear protective gear is proof enough for some that it is unacceptable. I have questions about these reports, claims, and conclusions for various reasons.

First of all, saying that tests have measured the presence of glyphosate need to be evaluated based on presumption and prior ignorance. Who was going around measuring levels of glyphosate, or substances that might be similar enough to register as glyphosate, before people got concerned about it? It’s not like there is a bucket of glyphosate molecules and they just look at them and say, “Oh, there’s one.” People, including educated ones, make assumptions that lead to erroneous conclusions. Doctors who have never seen a baby shaken have testified as experts that certain symptoms are due to this action. Now there is evidence that is a horrible assumption.

The human cells that were subjected to glyphosate were bare and unprotected in a lab dish. There was no skin. There was no immune system. There was no hand washing. A bunch of moist cells in a petri dish are going to readily absorb almost anything and have an unpleasant reaction. Sprinkle some salt on them and see what happens. Cover them in non-isotonic water and things won’t go well. But somehow, this research “result” about villain chemicals usually gets translated as people have already died or gotten cancer from a substance.

As for protective clothing, I wear gloves when I clean house because constant contact with water really irritates my skin. I wear a bicycle helmet because I crashed once and broke my face. I use potholders when cooking, because I’m smart. None of this protective gear is an indicator that substances or situations should be avoided. Rather, they allow me to make use of or enjoy this activities.

Again, I’m not saying we shouldn’t be careful about things. I just see some weak points in the things being said and I think it should be an honest discussion. There are even more weaknesses in research than most people know. How large and representative was the sample size? Were the results of high enough variability that conclusions are basically meaningless? How close was the experiment to real life? How well could outside factors be controlled and accounted for? What results does the researcher want? What peer pressure and popularity of results influence conclusions? What substantial research is being ignored?

If there has been intense testing about the affects of ingesting glyphosate that show that it is “practically non-toxic” at very high levels in rats, how much does it matter if there are traces of it around? Cookies are “practically non-toxic,” too. I speak from experience. And, as previously mentioned, there are lots of natural and normal things that people are exposed to every day that are, supposedly, also toxic.

On one hand, glyphosate has only been around for over 40 years. All of the worlds diseases cannot be attributed to it. On the other hand, it has been around for 40 years with no discernible bad effects on people when used properly. There is evidence that it does break down quickly in the soil, having a half life of 10-60 days. Much better than salt. And please, separate opinions about company politics from how the substance works. Rice is not more evil because a wicked overlord sells it.

Studies might be useful, but anecdotal experience is underrated. People and situations are varied. I have been using some glyphosate, in the form of Roundup, as part of my weed control for 20 years on my current property. Most of the weeds die, but new ones are always sprouting. Something about seeds … I still have all manner of insects, including lots of bees. The huge, fuzzy bumble bees are nearly huggable. There are tons of native lady bugs (I haven’t purchased them). We find praying mantises. The spiders are prolific. Ducks and little birdies are all around stealing my chickens’ grain. Mice live in the barn (until we trap them). Skunks have come to visit multiple times. And I’m still giving away food from last year’s garden. I just ran a half marathon barefoot and am training for a marathon and I’m the weakling of the group. I’d say we are healthy and have a thriving ecosystem.