Organic Herbicides: What They Are, What They Contain, and How to Use Them

In today’s world, where ecological and sustainable practices are becoming increasingly important, organic herbicides have completely changed the game in the last decade.

These herbicides have become the right solution for many individuals and organic farmers who are looking for a safer and responsible way of growing healthy crops without weeds.

These types of herbicides are an excellent way to control and get rid of weeds without worrying about harmful chemicals often associated with synthetic herbicides. They are renowned for their natural substances and eco-friendly approach to agriculture, gardening, and landscaping.

However, like many things in life, organic herbicides have their pros and cons.

Now, let’s explore the topic and see what they are, what they contain, who decides what’s organic and not, and if you can make your own at home.

What is an organic herbicide?

For those who wonder what is a natural organic herbicide, below you can find my simple description or organic herbicide definition that I always use to explain to others.

Organic herbicide is a type of weed killer made from natural substances that do not undergo any synthetic process.

Compared to other types of herbicides, organic herbicides decompose quickly due to natural substances that leave no residual effects. Also, the organic herbicides’ toxicity level is lower than the other synthetic ones, and they are considered safer and more environmentally friendly.

Organic herbicides can be either selective or non-selective.

What are organic herbicides used for?

Organic herbicides are used for controlling and eradicating weeds and other unwanted plants. They are commonly used in:

• Agriculture – the usage of organic herbicides for farming and agriculture influenced the appearance of the renowned organic agriculture, also known as organic farming, ecological farming, and biological farming.
• Home gardens – organic herbicides can be used to control the weeds in a home garden without having to worry about chemicals.
• Different lawns & public areas – Outdoor areas such as parks, trails, and lawns can be treated with organic herbicides too.
• Landscaping

Types of organic herbicides

Organic herbicides can be classified as:

• The spectrum of action: selective and non-selective herbicides. The majority of organic herbicides are non-selective ones, but there is a small group of selective organic herbicides too.
• Mode of action: pre-emergent and post-emergent.

How does organic herbicide work?

Organic herbicides work in different ways to control and kill weeds. It all depends on the active ingredient that the organic herbicide contains. As we have already seen, some ingredients are derived from natural sources and can be essential oils, vinegar, fatty acids, and so on.

Let’s see how each organic herbicide: works:

• Acetic acid / vinegar-based – The organic herbicide with vinegar/ acetic acid affects the weed’s tissues. The tissues of the plant dry out. This process is also known as desiccation. In the end, the weed wilts and dies.
• Citric acid-based – The citric acid organic weed killer works the same as the one based on vinegar. The citric acid organic herbicide works by desiccating or drying out the plant’s tissues.
• Essential oil-based – This organic herbicide disrupts the cell membranes of the weed, causing it to lose water and nutrients. This process is also called disruption of the cell membranes.
• Fatty acids-based (herbicidal soaps) – As the essential-oil ones, the fatty acids organic herbicides also work by affecting the cell membranes. The weed dehydrates and dies.
• Corn gluten meal-based – This organic weed killer with corn gluten meal works by inhibiting the weed’s root growth. The weed can no longer feed or grow, leading to its death.

To sum up, the organic weed killer can work by desiccating the plant, disrupting the plant’s cell membrane, or inhibiting root growth.

Organic herbicide vs. synthetic herbicide

Before jumping directly to the pros and cons of each type of herbicide, let’s first examine the primary distinctions between organic and synthetic herbicides.

Table 1. Distinctions between organic and synthetic herbicides

	Organic herbicides	Synthetic herbicides
Source	Based on natural substances derived from natural sources like plant extract, oils, and minerals.	Based on substances that were created synthetically in a laboratory.
Mode of action	Work slowly through desiccation or drying out, inhibition of root growth, and disruption of cell membranes.	Work faster by blocking the photosynthesis process, or targeting enzymes and proteins.
Persistence	Persist for a short amount of time because they break down easily.	Persist for a longer amount of time in soil and water.
Toxicity	Lower level of toxicity.	Higher level of toxicity.
Resistance	Less likely to lead to herbicide-resistant weeds.	Can contribute to the development of herbicide-resistant weeds.
Environmental Impact	Considered safer and more environmentally friendly.	They can have a greater impact on soil and water and are not considered environmentally friendly.

Now that we’ve established the primary differences between organic and synthetic herbicides, let’s take a look at the pros and cons of each.

Table 2. Pros and Cons of Organic and Synthetic Herbicides.

	Organic Herbicides	Synthetic Herbicides
Pros	Generally considered safer for the environment, animals, and humans. Can be homemade. DIY organic herbicides are cheaper than synthetic herbicides.	Highly effective at controlling and killing weeds. Can control and kill a large variety of weeds. They are cheap. Can be found in a variety of options like selective and non-selective. Require less frequent applications.
Cons	Require multiple applications. The majority of them are non-selective. If bought from stores, organic herbicides are more expensive than homemade solutions. May not be so effective in controlling some types of weeds.	Harmful for animals and humans. Not environmentally friendly. Can impact soil and water quality. May lead to herbicide-resistant weeds over time.

Weeds controlled and killed by organic herbicides

Depending on the active ingredient, some of the weeds that organic herbicides can control and kill include:

• Annual weeds: chickweed, crabgrass, and annual bluegrass
• Perennial weeds: dandelions, ground ivy, clover, and Canada thistle
• Broadleaf weeds: plantain, oxalis, chickweed, henbit, and purslane
• Grass weeds: bermudagrass, quackgrass, and tall fescue

However, organic herbicides may not be so effective in killing some types of weeds. Among them are the plants with deep roots like bindweed, the highly invasive ones like Japanese knotweed, and the ones that reached maturity.

How to make organic herbicide

Organic herbicides can be made by anyone at home. I will list 3 recipes that can help you control the weeds in the garden to a certain level.

At the same time, there are also some advantages when you decide to prepare a homemade organic herbicide:

Homemade Organic Herbicide

1Recipe

For the first homemade organic herbicide, you need the following ingredients:

• 1 gallon of white vinegar
• 1 cup of salt
• 1 tablespoon of dish soap

First, get a larger container in which to mix the ingredients. Add the three ingredients to the container and mix them until the salt dissolves. Once mixed, transfer the solution to the equipment you will be using for spraying. Spray directly on weeds. Ensure that there is a sufficient amount of organic herbicide on each weed. Repeat the process after a few days.

Does it really work?
Yes, this homemade organic herbicide works because normal vinegar has a concentration of 5% acetic acid. Salt, like vinegar, is also a desiccant that will cause the weed to wither. Last but not least, dish soap acts as a surfactant for herbicides and increases the absorption of organic herbicides in plant tissues.

2. Recipe

For this recipe you will need:

• 1 cup of white vinegar
• 1 cup of water
• 20 drops of clove essential oil
• 20 drops of cinnamon essential oil
• 20 drops of orange essential oil

3. Recipe

For this recipe you will need:

• 1 gallon of white vinegar
• 4 tablespoons of orange oil
• 4 tablespoons of liquid dish detergent

Place all ingredients into a spray bottle, shake well to mix them, and then spray the mixture directly onto the weeds. Apply the mixture to the weeds every day for about a week.

How to apply organic herbicide?

While the amount of substance combined with water may differ based on the active ingredient, applying organic herbicide is generally an easy process, as some general steps can be followed to ensure proper usage.

• Always read the label of the organic herbicide and follow the instructions for application rate, timing, and other safety precautions.
• Use the right application equipment for herbicides. You can choose to work with a backpack, hand-held sprayer, or tractor-mounted sprayer.
• Prepare the solution as written on the label. Some need to be mixed with water and others do not.
• Apply the organic herbicide on weeds and other unwanted vegetation. Be careful to not overspray on other plants.
• Apply multiple times. Organic herbicides must be re-applied a couple of times. Follow up with additional treatments as needed to achieve the desired level of control.

Organic herbicides belong to the category of contact herbicides, killing plants by destroying tissues. They are also non-selective, meaning that they kill everything when they touch it.

Be very careful when applying it.

When to apply organic herbicide?

The perfect time to apply organic herbicides is when the weeds are in their early growth stages. The younger they are, the easier they are to control.

You can apply the organic herbicide on days when the temperature exceeds 75° F.

It’s also important to apply the herbicide when the weather is dry, as rain or irrigation shortly after application can reduce its effectiveness.

How to choose a good organic herbicide?

Unlike other herbicides, organic herbicides are not available in large numbers on the market. Still, that does not make it easy to choose one for your needs.

So, what should you look for when choosing a good organic herbicide?

You can consider the following key factors:

• The type of weeds you want to control or kill. Identify them before you buy something. Each organic herbicide contains an active ingredient. So, you want to take one that has the right formula that targets those weeds.
• Application method. Some organic herbicides already come in a spray bottle, which makes your work easier. Others come in larger containers that require mixing with water in different spray bottles.
• The amount of product. If you have a larger surface to spray, then you must buy a product that is sufficient to treat large areas.
• Reviews. If you buy online, it doesn’t hurt to take a look at the product reviews.
• Budget and price. Organic herbicides vary in price, so keep your budget in mind when buying one. You can always make your own organic herbicide at home too.

The active ingredients in organic herbicides

The most common active ingredients in organic herbicides are the following:

• Acetic acid or vinegar
• Citric acid
• d-limonene (Citrus Oil)
• Essential oils like clove oil (eugenol)or clove leaf oil, cinnamon oil, summary savory, red thyme, peppermint oil
• Chelated iron
• Lemon grass Oil
• Olive oil
• Lecithin
• Yucca extract
• Corn gluten meal
• 2-Phenethyl propionate
• Sodium lauryl sulfate
• Ammonium nonanoate
• Pelargonic acid
• Fatty acids (herbicidal soaps)
• Chelated iron FeHEDTA

The active ingredients in organic herbicides are closely monitored by the National Organic Standards Board and the National Organic Program. They maintain the list of all approved ingredients for organic herbicides.

I hope this article helps you understand more about organic herbicides.

To make your work easier, I have created an article with a list of organic herbicides that you can use, categorized by the type of weed killer and where you can buy them.

If you have any questions or concerns, or want to share your experience with organic herbicides, don’t hesitate to use the comment form below. In this way, we can grow our community and exchange experiences.