Happy spring everyone! Tis the season for abundant plant growth- good and the bad! It is also the time of year when TERRIBLE gardening advice gets shared on social media. I am taking on this myth that mixing vinegar, salt, and dish soap to control weeds is an “earth friendly” alternative to applying herbicide. Instead of getting mad about it, I have decided to speak up, representing scientific information to encourage best practices and debunk old wives’ tales.
This post is not intended to offend anyone, but rather shed some light on the reality of applying “chemicals” in your garden- no snarky comments will be tolerated. It is imperative to remember that vinegar, salt, and dish soap are also chemicals, so please STOP sharing bad information (in general) and recognize that even if you don’t understand the chemistry of herbicide (specifically glyphosate) that doesn’t make the product unsafe to use per the labelled instructions.
DO YOU LOVE ORGANIC GARDENING?
Me too! I recently debuted a new presentation that dives deep into the best organic gardening practices for home gardeners. It is chalk full of practical information (and products) that will be useful for every gardener, no matter the experience level! Contact me, as I would be happy to present this topic at your next gardening event! Brie@BrieGrows.com
WHAT IS PESTICIDE?
First, let's discuss the terminology revolving around the discussion because it is often misused. To be fair, until recently I have been misusing this word, making it all about insects. After a discussion on the Brie Grows Facebook page, I decided to look it up. Turns out PESTICIDE is an umbrella term for any product used to control “nature” so to speak. This includes insecticides (applied to kill insects), herbicides (to control unwanted plants), fungicides (managing disease), and rodenticides (to deter browsing animals). This blog is specifically focused on weed control and debunking the idea that household vinegar is a better or safer solution than commonly available (and generally misunderstood) herbicide.
WHAT IS AN HERBICIDE?
Herbicide is applied to specifically kills plant, not insects. Internet sources like to allude that by spraying herbicide you are directly killing bugs, but that isn’t really accurate. By applying herbicide, you are killing plants which can be nectar sources and create habitat for bugs. This can lead to decline of insect populations, but the herbicide is not directly killing the insect, that just isn’t how the chemistry works.
The good news is there are many great organic pest controls, including BT (Bacillus thuringiensis) which controls unwanted caterpillar infestations, Diatomaceous Earth which cuts soft bodied insects like slugs and snails resulting in death via dehydration, Insecticidal Soap, a great reactive option for dealing with aphids, spider mites, whitefly and other common insects that suck on new growth, and Horticultural Oil which is ideal for controlling scale on broadleaf evergreens like Camellias. But that is a separate discussion for another day!
BAD INFORMATION ABOUNDS
In recent presentations I’ve been spending a few minutes explaining common gardening products and debunking bad advice that constantly spreads on Facebook, like this meme that has been shared nearly a million times.
I wish I was creative enough to make a counter meme that would go viral, but alas that is not my area of expertise.
PLEASE STOP SHARING THIS! When you see it, share a link to this blog in the comments. Bad information must be combatted with good!
If you don’t feel comfortable spraying your garden, don’t! Hand weed and engage the ground plane with more plants- that’s what I do! Open mulch space will always be high maintenance! But remember, vinegar is not a safer alternative for management!!!!
In reaction to this I posted a video about spring seedling identification, both good and bad. I also address this STUPID idea that spraying vinegar, salt, and dish soap is safer than using herbicide- ITS NOT! Click below to watch the video and learn more.
Another fun and easy solution is Flamethrowing!! I won’t deny that since getting a flamethrower as a gift from my garden helper Aidan, my life has changed for the better! It is the best tool that I never knew I was missing, though sometimes nothing beats a little time on your hands and knees pulling out the unwanted plants. Here is a video showing both methods: flamethrowing to kill invasive Hellebore seedlings and hand removing winter weeds. The moral of the story is THERE IS NO ONE SIMPLE ANSWER! You need to use all the tool in your toolbox.
WHY THE VINEGAR + SALT+ SOAP CONCOCTION IS NOT THE RIGHT CHOICE
If you are trying to avoid “chemicals” in your garden, you should recognize that vinegar is also technically a chemical. Vinegar contains acetic acid, which can lower the pH of the soil, making it less hospitable to desirable plants. Salt, when applied in high concentrations, can accumulate in the soil, leading to long-term damage and making it challenging for plants to thrive. Dish soap, while not harmful in small quantities, can also disrupt the balance of beneficial microorganisms in the soil. Therefore, this myth is BUSTED!
Household vinegar typically contains 4-6% acetic acid. That isn't strong enough to kill the weeds to the root. Vinegar doesn’t have a mechanism to be systemically absorbed into the plant and acts as a contact herbicide. This means it kills the part of the plant it encounters only. Stronger concentrations of vinegar can be effective, but will also impact your soil PH level, rendering the sprayed area unsuitable for growing. Vinegar is also highly caustic to amphibians, so if you enjoy having frogs in your garden leave the vinegar in your pantry!
Here are a few more reasons why spraying vinegar in your garden can be detrimental:
Non-selective action: Vinegar is non-selective, meaning it kills or damages any plant it comes into contact with, including desirable plants in your garden. This makes it difficult to target weeds without harming nearby ornamental plants, vegetables, or other desired vegetation.
Root damage: Vinegar-based herbicides can kill weeds by desiccating their foliage, but they may not effectively kill the roots of perennial weeds. This can result in regrowth from the root system, requiring repeated applications or manual removal to fully eradicate the weed.
Soil acidity: Vinegar is acidic, and repeated applications of vinegar-based herbicides can lower the pH of the soil, making it more acidic. This can adversely affect the growth and health of plants that prefer neutral or alkaline soil conditions, leading to nutrient imbalances and reduced plant vigor.
Environmental impact: While vinegar is considered a natural product, excessive use of vinegar-based herbicides can still have negative environmental consequences. Runoff from sprayed areas can leach into nearby water bodies, potentially harming aquatic organisms and disrupting ecosystems.
Safety concerns: Concentrated vinegar solutions can cause skin and eye irritation, and inhalation of vinegar fumes may irritate the respiratory tract. Additionally, accidental ingestion of vinegar-based herbicides can cause gastrointestinal irritation and other adverse health effects, particularly in pets and children.
Overall, while vinegar-based herbicides may offer a natural alternative to synthetic herbicides, it's important to use them judiciously and with caution in the garden. Alternatives such as manual weeding, mulching, or using targeted herbicides with less potential for unintended harm to desirable plants and the environment may be more suitable for weed control in garden settings. My recommendation is JUST SAY NO! Use vinegar to make salad dressing, pickles, or clean your floors!
WHAT CAN YOU DO THAT IS SAFE?
Note I used the word DO and not SRAY? Perhaps the easiest solution to avoid spraying is to focus on a more pro-active solution to help avoid weed infestations from the start: engage the ground plane! If you have open areas in your landscape, it is inevitable plants will grow. Think critically about open mulch space and look to easy solutions like direct seeding annual edibles and flowers to fill in the gaps temporarily. I call this “Cottage Gardening” and it creates dynamic displays that are inexpensive and easy to create. I have about a thousand videos providing step by step instructions on exactly how to utilize this approach in your home garden.
Another fun and easy solution is Flamethrowing!! I won’t deny that since getting a flamethrower as a gift from my garden helper Aidan, my life has changed for the better! It is the best tool that I have only recently been utilizing, though sometimes nothing beats a little time on your hands and knees pulling out the unwanted plants. Here is a video showing both methods: flamethrowing to kill invasive Hellebore seedlings and hand removing winter weeds. The moral of the story is THERE IS NO SIMPLE ANSWER! You need to use all the tools in your toolbox.
IS “ROUND UP” REALLY BETTER?
First, I am not advising you to spray herbicide of any kind and I am not on Scott’s payroll to influence you to purchase Roundup (Yes, Scott’s bought the brand name after the patent for the active chemical glyphosate expired). There are simple alternatives to spraying (as I have mentioned above) including ground plane engagement, hand removal, and my favorite, flamethrowing to burn the weeds away! However, I cannot dismiss the reality that synthetic herbicides can be an important tool in land management. It is crucial to remember they are not the only tool, but when used appropriately, according to labelled instructions, they can be effective and safe.
WHY IS EVERYONE AFRAID OF GLYPHOSATE?
It is important to note that it is very likely that you have consumed Round Up in your lifetime, and it is not unreasonable to find that reality to be undesirable. Particularly if you eat processed foods with high fructose corn syrup and other sweeteners, beware, those crops have been modified to be resistant to glyphosate so they can be over sprayed for weed control.
"Roundup Ready" crops are genetically modified organisms (GMOs) that have been engineered to tolerate glyphosate, the active ingredient in the herbicide Roundup. This trait allows farmers to effectively control weeds by spraying glyphosate-based herbicides directly onto the crops without harming them. Some of the most common Roundup Ready crops include:
Soybeans: Roundup Ready soybeans were among the first genetically modified crops to be commercially available. They are widely cultivated in many countries around the world.
Corn (Maize): Roundup Ready corn varieties are genetically engineered to tolerate glyphosate, providing farmers with a convenient weed management option during the growing season.
Cotton: Roundup Ready cotton varieties have been developed to withstand glyphosate applications, allowing for effective weed control in cotton fields.
Canola: Roundup Ready canola, also known as rapeseed, is genetically modified to tolerate glyphosate herbicides, providing farmers with a tool for weed management in canola crops.
Alfalfa: Roundup Ready alfalfa varieties have been developed to tolerate glyphosate applications, offering farmers improved weed control options in alfalfa fields.
Sugar Beets: Roundup Ready sugar beet varieties have been genetically modified to tolerate glyphosate herbicides, providing growers with effective weed control solutions in sugar beet fields.
It's important to note that while Roundup Ready crops offer farmers a convenient weed management tool, the development of herbicide-resistant weeds is a growing challenge in agriculture, highlighting the importance of integrated weed management practices to sustainably manage populations of undesirable plants.
As a home gardener you do not have access to any GMO “Roundup Ready” seed, so this really isn’t even a subject that should keep you up at night. However, as I mentioned above, there is a high chance that you have consumed glyphosate residue when eating food from the grocery store. If that makes you uncomfortable, stay away from processed food, buy organic, support local farmers, and grow more food in your home garden. In short, be the change you want to see.
HOW DOES GLYPHOSATE WORK?
Understanding organic chemistry is not easy, and to be fair, the internet explanation of these questions doesn’t make it any simpler. “The mechanism of action of glyphosate is to block the activity of the enzyme called 5-enol-pyruvyl-shikimate-3-phosphate synthase (EPSPS).” Okay, did that make sense to you, because it is meaningless to me. Read below for the “Brie version” that hopefully makes more sense to normal people.
The shikimic acid pathway is necessary for plants to photosynthesize, aka collect energy. Glyphosate applications disrupt the synthesis of essential amino acids in plants. Without that enzyme, plants are unable to produce other proteins that are essential to growth, resulting in yellow coloration and death, due to the inability to collect energy from the sun. It must be absorbed into green material to work and is ineffective in temps below 50°f.
The exact time that it takes for Roundup to break down in the soil remains a strong point of debate in the scientific community. Rainfall, humidity, and the quantity sprayed on the soil all play a role in determining the “half-life” of glyphosate. FYI half-life refers to how much time it takes for a certain amount of herbicide to be reduced in half.
Cornell University researchers found that glyphosate has a half-life in soil of between 1 and 174 days, which is 71% of the USDA’s maximum half-life range. Some studies indicate that Roundup becomes harmless to nearby vegetation quickly, and plants accidentally sprayed with Roundup can be washed immediately after application to prevent absorption by the leaves. Compared to other herbicides this has a very short active duration in the soil, making it much safer for common use. (Keep reading to learn more). It is a POST EMERGENT herbicide, aka you see weeds and spray them as a reaction, not a prevention.
WHAT ARE PRE-EMERGENT HERBICIDES?
In contrast pre-emergent herbicide (such as Preen for home gardeners), PREVENT seeds from germinating. Pre-emergent herbicides work by forming a barrier in the soil that inhibits the growth of weed seedlings or prevents the germination of weed seeds altogether. This barrier can be chemical, physical, or biological in nature, depending on the specific herbicide formulation and mode of action.
Chemical pre-emergent herbicides typically work by inhibiting key metabolic processes in weed seeds, such as cell division or root development, preventing them from germinating or establishing roots after germination. Common active ingredients in chemical pre-emergent herbicides include dinitroanilines, dinitroanaline, and isoxazolidinones.
Physical pre-emergent herbicides create a barrier on the soil surface that prevents sunlight from reaching weed seeds, inhibiting their germination and growth. This type of pre-emergent herbicide is often applied as a mulch or layer of material, such as plastic or organic mulch, that physically blocks weed seeds from receiving light.
Biological pre-emergent herbicides utilize naturally occurring microorganisms or plant extracts to inhibit weed seed germination or growth. These products work by competing with weed seeds for nutrients or by producing compounds that inhibit weed seed germination or root development.
Pre-emergent herbicides are commonly used in agriculture, landscaping, and turf management to prevent weed infestations and reduce the need for post-emergent weed control measures. However, it's important to note that pre-emergent herbicides may also affect desirable plants if not applied correctly, so proper application timing, dosage, and placement are essential for effective weed control while minimizing environmental impact. Additionally, some pre-emergent herbicides have residual activity in the soil, so care should be taken to avoid planting sensitive crops or ornamental plants in treated areas for a certain period after application.
For consumers this is often sold as “weed and feed” meaning fertilizer and granular herbicide is combined to be spread primarily in lawns, but also landscape areas. They need to be watered in immediately after application to become effective. Oddly, no one seems to be bothered by this and often pay lawn care services to apply it. Of course, there are environmental risks associated with this category of herbicide but that hasn’t captured the public’s attention, as I haven’t seen any ridiculous memes targeting this practice that is abundant each spring. If you want to garden like me, growing from direct seeding to engage the ground plane you cannot use pre-emergent herbicide because none of your desirable seeds will germinate.
WHAT ARE THE HERBICIDES CONTAMINATING COMPOST?
If you buy compost, it is likely you have heard of or experienced first-hand a new and horrible phenomenon called “Killer Compost”. I fall into the category of “been there” and it is a sad affair. As a result, I took a crash course in researching what the cause is and let me tell you, it’s a giant, complicated rabbit hole. The kind of subject that makes you realize the world is GREY- not black and white. There really is no good or bad for managing life in the modern day. An advancement in one category is a drawback in another. The culprit for contaminated soil most often is a relatively new class of herbicides called pyridine carboxylic acids.
In my research, Aminopyralids were one of the more commonly applied chemistries in this class of selective herbicides commonly used in agriculture and horticulture to control broadleaf weeds and certain invasive plant species. Aminopyralid works by disrupting the growth and development of susceptible plants, ultimately leading to their death.
One of the distinguishing features of aminopyralid herbicides is their persistence in the soil, which allows for long-lasting weed control with a single application. This persistence is due to the chemical properties of aminopyralid, which make it resistant to degradation by soil microbes (AKA Half-Life). This is also a major distinction from glyphosate, which has a very short half-life in soil by comparison.
Aminopyralid herbicides are typically applied to target weeds either as foliar sprays or a soil application. They are absorbed by the leaves or roots of the weeds and translocated throughout the plant, where they interfere with essential physiological processes, such as cell division and protein synthesis.
While aminopyralid herbicides are effective against a wide range of weeds, including many that are resistant to other herbicides, they can also pose challenges due to their persistence in the environment. Residual aminopyralid in composted manure and hay can persist through the composting process and affect the growth of sensitive crops, such as tomatoes, potatoes, and other broadleaf vegetables. This is heartbreaking for home gardeners, including myself.
Therefore, it's important for users of aminopyralid herbicides to carefully follow label instructions and guidelines to minimize the risk of unintended damage to non-target plants. In my experience the Department of Transportation (DOT) and energy companies spraying under power lines are often the original source of aminopyralid escaping their intended location and running into water sources that are farm adjacent.
Additionally, proper disposal of contaminated materials and monitoring of soil and water quality are essential practices to mitigate potential environmental impacts associated with the use of aminopyralid herbicides. In my opinion, THIS IS A MUCH BIGGER PROBLEM than Round Up. Sadly, there are no memes circulating about this problem. However, when consumers buy contaminated compost, it feels like the end of days.
WHY I LOVE AND USE SOIL3 COMPOST
I can only write from own my experience, and I have purchased tainted compost from many different, nation-wide suppliers in my 20+ years gardening. Most compost companies have turned a blind eye to this on-going issue, with one exception, Soil3, a company I am proud to work with. When aminopyralid compromised their product, they worked tirelessly with weed scientists from around the country to find a solution. This is how Veggie Mix was created.
The addition of ground aged pine bark, wood fiber, and activated charcoal has proven to be very effective in neutralizing any potential contamination from pyridine carboxylic acids. They also perform environmental biological assays which are field-based experiments used to measure the potency, concentration, or biological activity of a substance by observing its effects on living organisms. This process has enabled Soil3 to guarantee the products they sell to the public. You can learn more about Soil3 compost here.
HOW MANY DIFFERENT HERBICIDES ARE THERE?
I first acquired my Pesticide Applicators License in 1999 and managed it for many years when I was a fulltime grower and propagator in the nursery industry. It was my job to understand and use chemical technologies to make growing plants cost effective. Since transitioning into consumer horticulture communications maintaining this accreditation became unnecessary, and since I am an organic home gardener, I stopped paying attention. Writing this article has been very helpful in getting me back up to speed. In short, there are a lot of different chemistries on the market.
There are several different ways to classify herbicides, including by their chemical composition, mode of action, and target weeds. One common classification system categorizes herbicides into several main classes based on their mode of action, which refers to the specific biochemical processes they disrupt in plants. According to this system, there are approximately 30 different herbicide classes. Some of the most used herbicide classes include:
Glyphosate: (aka “Round Up) This non-selective herbicide inhibits the enzyme EPSP synthase, disrupting the synthesis of essential amino acids in plants.
ALS Inhibitors (Acetolactate Synthase Inhibitors): These herbicides interfere with the production of branched-chain amino acids, leading to the death of susceptible plants. Examples include sulfonylureas, imidazolinones, and triazolopyrimidines.
Photosystem II Inhibitors: Herbicides in this class block electron transport during photosynthesis by binding to the D1 protein in photosystem II. Examples include triazines and urea derivatives.
Photosystem I Inhibitors: These herbicides disrupt electron transport in photosystem I, leading to the production of reactive oxygen species and cell damage. Examples include bipyridiliums (such as paraquat).
Synthetic Auxins: These herbicides mimic the action of the plant hormone auxin, causing uncontrolled growth and eventual death in susceptible plants. Examples include 2,4-D and dicamba.
Microtubule Inhibitors: Herbicides in this class disrupt cell division by interfering with the formation of microtubules, essential structures for cell division and growth. Examples include dinitroanilines and benzamides.
Cell Division Inhibitors (Mitosis Inhibitors): These herbicides disrupt mitosis, the process of cell division, leading to abnormal growth and eventual plant death. Examples include dinitroanilines and pyridines.
HPPD Inhibitors (4-Hydroxyphenylpyruvate Dioxygenase Inhibitors): These herbicides inhibit the enzyme HPPD, disrupting the synthesis of carotenoids and leading to chlorosis and bleaching in susceptible plants. Examples include isoxazoles and pyrazoles.
These are just a few examples of herbicide classes, and there are many more with distinct modes of action and chemical properties. Understanding the different classes of herbicides is essential for effective weed management and preventing the development of herbicide resistance in weed populations. Luckily as home gardeners, these issues are not top of our list to solve. Remember, if you don’t want to apply chemicals in your garden stick to hand weeding and engaging the ground plane with desirable plants.
WANT TO LEARN MORE?
It is important to be a well-informed consumer, gardener, and citizen. That responsibility falls you on to decipher the good from the bad, which can be a challenge when Google is your portal to education. Search for information from trusted sources like Land Grant Universities. My alma mater Purdue University has many great resources available, as does NC State, my local go-to source for science-based information. But some random blog (yes, I get the irony here) is not always going to be a reliable source for scientific based data.
It’s up to you: if you feel uncomfortable using chemicals in your garden, don’t apply them. You can garden without herbicide quite easily. But PLEASE don’t trust and share scientifically untrue memes, like using vinegar as an alternative.
Thanks for taking the time to read this blog. I sincerely hope it helps shed some light on the topic of herbicides, gardening, and why we can’t trust misinformation floating on the internet.