Dicamba vs Glyphosate (Herbicide Comparison)

In a nutshell, Dicamba and Glyphosate are both highly effective herbicides that can be used to target either certain species of plants and weeds or as a broad-spectrum herbicide.

Dicamba and/or Glyphosate can be effective tools when it comes to lawn care management and improvement, however, they perform different functions and should be used according to a specific outcome that you want to achieve. And I’m going to talk about these scenarios and things to consider below.

The Difference Between Dicamba vs Glyphosate

Glyphosate is a broad-spectrum systemic herbicide. What does that mean? Well, to put it bluntly, it will kill any and every plant that it comes into contact with. Glyphosate is extremely potent and has the capability of killing a wide variety of grass and weed species.

Dicamba is a selective herbicide that is most commonly used in combating broadleaf weed species, post-emergence. Dicamba comes in either a salt formulation or an acid formulation.

We will dive into the finer details of each herbicide a bit later and discuss the ins and outs of each one, but as a top-level comparison, that is the most obvious difference between the two.

In-Depth Comparison of Dicamba vs Glyphosate

Now I’m going to go into more depth, comparing the use of Dicamba vs Glyphosate on lawns, covering things like how they both work, how quickly you can expect results, as well as talking about their respective safety profiles.

How Are They Applied?

Dicamba Application

With Dicamba’s primary focus being on post-emergence, the best form of application is through spot treatment. It’s best to use a coarse or narrow nozzle to apply the herbicide directly onto the weed as opposed to an open or misting nozzle which may cause drift, resulting in the Dicamba coming into contact with plant species you want to keep.

Glyphosate Application

When it comes to Glyphosate it is not so much about how to physically apply it, rather the steps you have to take in order for it to work effectively. What I mean by that is to read the label on the product packaging carefully and understand the correct mixing and application rates. Certain species or areas that you wish to spray may require different strengths of a Glyphosate mixture and in some cases, a follow-up application will also be necessary.

Remember because Glyphosate is a broad-spectrum herbicide and non-selective by nature, its application needs to be done carefully and in a controlled manner. It is best to apply Glyphosate directly onto the leaves of the plant you want to be removed. Should you wish to cover a larger area then application with a sprayer can be done but try to pick a still day so as to prevent drift of the herbicide onto neighboring plants.

Glyphosate is most effective at temperatures above 60 degrees Fahrenheit and with no rainfall or water applied to the plants at least 48 hours after application.

What Weeds Will They Kill?

Dicamba Works On…

We previously touched on Dicamba being a selective herbicide that targets broad-leafed weeds. Let’s elaborate a little on what the term “broad-leafed weeds” actually means.

The term “broadleaf” refers to any plants that have a flat, relatively broad surface and are most commonly marked with a network of visible veins. Dandelion, Ground Ivy, and Clover are good examples of broadleaf plants that can be taken out with Dicamba.

It is also effective on plants with woody stems.

Glyphosate Works On…

Glyphosate kills not only the same broad-leaved species as Dicamba, but grass species found in lawns too. The list of plant species that Glyphosates will negatively affect is so long that it would need its own article to talk about them all. If you are unsure whether or not a species will die from Glyphosate, it’s honestly best to just assume that it will.

How Do They Work?

Dicamba Method

Auxins are hormones found within all living plants. They are responsible for the amount, type, and promotion of plant growth. Dicamba mimics this hormone by entering the plant at the leaves and roots, effectively replacing the role of the hormone at the binding stage.

This interference by Dicamba leads to excessive or rather abnormal plant growth. The plant outgrows its nutrient supply at such a rate that it dies.

Glyphosate Method

Glyphosate prevents plants from producing certain proteins that are vital for plant growth, which in turn stops a specific enzyme pathway. That enzyme pathway is called the shikimic acid pathway.

In essence, the plant is starved of essential vitamins, minerals, and amino acids that it needs to perform everyday functions.

How Fast Are the Results?

Dicamba Visible Results

The average length of time that Dicamba takes to effectively kill the plant is 2 to 3 weeks. There are cases where weeds can be persistent when environmental conditions such as rain or low temperatures prevent the Dicamba from effectively penetrating the plant, in which case a follow-up application is usually needed.

Dicamba can also remain active in the soil for up to 14 days after the first application.

Glyphosate Visible Results

The first signs of effective treatment will be the wilting of leaves which generally occurs within 12 – 24 hours of application. The plant, including the roots, is completely dead within 7 to 14 days.

It is important to mention that Glyphosate products should be given sufficient time to infiltrate the plant and effectively kill it. Glyphosate relies on the plant’s internal biological processes to carry this out. Once an application is made it is important to leave the plants, do not cut them, or pull them out, for at least 10 days after application so that the herbicide can move through the plant and down to its roots.

Is One Safer Than the Other?

Safety precautions should always be taken when handling herbicides, the instructions thoroughly read over and protective gear worn.

Dicamba Safety Info

Dicamba in its purest form is fairly low in toxicity and if fumes are inhaled the person may experience dizziness and irritation of the nose. Dicamba cannot be easily absorbed through the skin of humans although a mild form of skin irritation may occur.

There are reports of vomiting, stomach cramps, and diarrhea from people that have ingested it. However, there are no reported cases of death and very few findings associating it with cancer.

Glyphosate Safety Info

Glyphosates pose no threat to human (or children’s) health when used correctly as per label instructions. It is not likely to have carcinogenic effects. Glyphosates are not easily absorbed through the skin and are unmetabolized when taken orally. This means that once ingested it passes through the body without being absorbed, or at very low volumes, and it does not bioaccumulate in the body.

Glyphosates are generally considered safe herbicides to work with. Although from time to time debate arises as to this assurance, and rightfully so, as we should never stop evaluating how herbicides are influencing human health.

When is Dicamba a Good Option?

Dicamba is a good option to use when you know the specific plant species within your lawn that you want to remove. On days when there is a slight breeze blowing and you are worried that the use of Glyphosate may affect the nearby plants, then it is best to go with a direct application to any broadleaf weeds of Dicamba.

When is Glyphosate a Good Option?

Glyphosate is the go-to option when you want to start again or clear a specific area and completely change the plants growing there.

With it being non-selective, its effectiveness is broad and unselective. Good examples would be when you want to clear an entire piece of land, or once an old flower bed is pulled out. It can be used to kill anything that sprouts back up so as not to compete with your new plantings.

Another good time to grab the Glyphosate is when your lawn has crept someplace where it was never intended to occupy, for instance in between the cracks of your paving or walkway.

Can I Mix Dicamba and Glyphosate?

The short answer to this is yes, Dicamba and Glyphosate can be mixed. However, the better question would be, is it necessary to mix the two herbicides?

Mixing of these two herbicides is commonly done in agriculture where large areas are sprayed, usually crop fields. The mixing is done in large spray tanks and the reason for this is that the Glyphosate controls the initial development of broad-leaved weeds while the Dicamba offers full-season broadleaf weed control.

In my opinion, it wouldn’t be necessary to mix the two when it comes to lawn care. Both herbicides work fairly quickly at killing weeds and their signs of effectiveness are evident after 3 to 4 days. Any weeds sprayed with either Glyphosate or Dicamba that show no obvious signs of being affected can receive a follow-up spray from a stronger application or an alternative herbicide.

Of course, for those that are wanting to completely replace a lawn and remove all vegetation then mixing Dicamba and Glyphosate would help as the Glyphosate would cover any weeds that may have resistance against Dicamba and vice versa.

Summary

So there you go, when you walk into your garden shed and are scratching your head about which herbicide to use, Dicamba or Glyphosate, remember this: If dealing with older, established weeds within an established lawn, go with Dicamba spot treatment. When you have taken too long to plant the bed you cleared for a vegetable patch, and it is being invaded (again) by weeds and lawngrasses alike, nuke it with the Glyphosate.