Will Pelargonic Acid Kill Weeds?


Understanding Pelargonic Acid

Pelargonic acid, also known as nonanoic acid, does have the ability to kill weeds. It’s a natural fatty acid found in many plants and animals. When it’s applied as a herbicide, pelargonic acid can effectively control both broadleaf and grass weeds due to its non-selective properties.

Chemical Profile:

  • Name: Pelargonic acid (Nonanoic acid)
  • Type: Fatty Acid
  • Mode of Action: Desiccant

By disrupting the cellular structure of weed foliage it contacts, pelargonic acid causes the plants to dry out and die. This makes it a useful treatment for younger weeds, which are more susceptible to this type of control.

Using Pelargonic Acid:

  • Target: Younger weeds for best results
  • Application: Direct contact needed
  • Effect: Causes plants to desiccate

Since it is a contact herbicide, you have to ensure that pelargonic acid directly touches the foliage of the weeds you intend to eradicate. It is relatively fast-acting, showing effects shortly after application.


  • Fast-acting
  • Non-selective
  • Natural compound

Pelargonic acid usage aligns well with environmentally conscious practices as it is a naturally occurring substance. However, you should always adhere to the recommended application rates and safety guidelines when using any herbicide, including organic ones, to mitigate any risk to non-target plants or the environment.

Application Techniques

When you choose to tackle weeds with pelargonic acid, your approach will vary depending on the product form. Whether it’s a ready-to-use spray solution or a more concentrated form, the key is in how you apply the product to ensure effective weed control.

Spraying Solutions

For immediate action, sprayer-based solutions are your go-to. When using a weedkiller spray containing pelargonic acid, ensure you have a sprayer with a nozzle that provides uniform coverage. Apply when the weeds are actively growing, targeting the leaves for the best absorption. Keep in mind that multiple applications might be required for tougher weeds.

Gel and Concentrate Forms

If you’re dealing with persistent weeds in specific areas, consider using pelargonic acid in gel form. You can apply it directly to the weed, reducing the risk of affecting surrounding plants. For larger areas or more economical use, choose concentrate forms of the weedkiller. You’ll need to dilute it according to the manufacturer’s instructions before application. Remember to wear protective gear to avoid skin irritation.

Environmental and Safety Concerns

When considering the use of pelargonic acid as a herbicide, it’s imperative to understand its effects beyond weed control. The critical aspects here encompass not just the safety protocols for human and animal health but also the potential influences on wildlife and ecosystems.

Human and Animal Health

Your safety is paramount when handling pelargonic acid. As per the US Environmental Protection Agency, appropriate safety instructions should be closely followed to minimise health risks. With respect to potential cancer risks or effects on metabolism, there is no substantial evidence suggesting a direct link. However, as with any chemical, proper use and handling could mitigate any unforeseen health impacts. Protective clothing and gear are highly recommended to prevent skin and eye irritation during application.

Cautious use is also advocated to protect domestic animals – pets may experience discomfort if they come into direct contact with treated areas before the substance has dried.

Wildlife and Ecosystem Impact

The ecological ramifications of pelargonic acid use should be carefully considered. Studies suggest that when applied correctly following guidelines, it does not significantly contribute to environmental pollution. In fact, the advantage of pelargonic acid lies in its relatively quick degradation, which limits prolonged impact on treated areas.

Despite this, indiscriminate use can still pose a hazard. For instance, directly spraying bodies of water can be detrimental to aquatic life. Always ensure to apply away from ponds, lakes, and streams to prevent contamination.

While bees and other pollinators are less likely to be affected due to the non-systemic nature of the substance, it’s still advisable to spray during periods when these insects are less active, such as early morning or late evening, to avoid direct contact.

Comparing Weed Control Products

When selecting a weed control product, you need to consider effectiveness, application method, and the environmental impact of the ingredients. Pelargonic acid and glyphosate are two widely used compounds, each with their specific applications and effects.

Pelargonic Acid vs Glyphosate

Pelargonic Acid, a naturally occurring fatty acid, is found in many commercial weed killers, including products from Neudorff. It acts as a contact weed killer, meaning it destroys plant tissue it comes into direct contact with. This makes it particularly effective for visible, surface-level weeds, such as those found on block paving. It’s important to note that while pelargonic acid is considered a more natural alternative to synthetic herbicides, it requires thorough coverage of the weeds for full effectiveness.

In contrast, Glyphosate is a systemic herbicide present in products like Roundup. It is absorbed through the foliage and then transported throughout the plant to inhibit essential growth enzymes. Glyphosate-based products are typically non-selective, meaning they can eliminate a broad spectrum of weeds but may also affect unintended plants if applied improperly.

Features Pelargonic Acid Glyphosate
Type of Herbicide Contact Systemic
Speed of Action Fast-acting Slower, requires time to be systemic
Environmental Persistence Rapidly degrades Persists longer
Effectiveness on Large or Rooted Weeds Less effective More effective
Toxicity to Non-target Plants Low – minimal residual activity Higher – careful application needed

Commercial and Home-Made Solutions

For everyday garden maintenance, commercial weed killers that contain pelargonic acid, like Neudorff’s Roundup Natural, provide a convenient option. They are formulated for ease of use and often come with applicators designed for targeted spraying, reducing the risk of affecting surrounding plants.

For a more DIY approach, some gardeners create home-made solutions using pelargonic acid. However, accuracy of dilution and application is crucial to ensure safety and effectiveness. As always, when handling any weed control product, it is essential to follow manufacturer guidelines to protect yourself, your plants, and the environment.

Alternative Weed Management Strategies

When examining the battle against unwanted vegetation in your garden, consider alternative methods that do not involve chemical herbicides. These approaches are centred around physically blocking or applying thermal techniques to deal with weeds.

Physical Barriers and Mulching

Physical barriers, such as landscaping fabrics, can effectively suppress weed germination by blocking sunlight. They’re laid across the soil surface and can be covered with decorative mulch for an aesthetically pleasing finish. Mulching, using a variety of materials like hay, wood chips or cardboard, provides a natural layer that improves soil health and suppresses weeds. Ensure the mulch layer is at least a few inches thick to maximise effectiveness.

Thermal Weed Control Methods

For thermal weed control, options include weed burners which use a direct flame to incinerate weeds down to the root. Traditional burners are gas-powered, but electric weed burners offer a flameless alternative using intense heat. This method is instant and can be more precise. Secondly, applying hot water—just off the boil—directly onto weeds causes plant cells to burst, thus killing them. This is a safe, instantaneous method, particularly useful for path or patio weeds.

Effects on Domestic and Wild Flora

In your quest to maintain a pristine garden, it’s crucial to consider the impact of weed control strategies on both domestic and wild flora. Pelargonic acid is known for its effectiveness in weed management, but understanding its selectivity and influence on non-target plants is key.

Non-Target Plant Safety

You may find a variety of plants in your garden ranging from delicate geraniums to hardy moss. When applying pelargonic acid, it’s essential to be mindful of its non-selective nature. This weed killer can cause harm to any foliage it comes into contact with. For instance, while pelargonic acid provides excellent weed control, your beloved pelargoniums might also suffer if sprayed inadvertently.

Promoting Plant Health

Despite its broad-spectrum action, carefully utilising pelargonic acid can be advantageous for promoting plant health by reducing weed competition. Weeds can serve as hosts for various pests, which might otherwise target your domestic plants. Successful weed eradication helps ensure that nutrients and sunlight are reserved for your desired flora, such as ornamental geraniums, rather than invasive weeds. It’s important to apply pelargonic acid as a directed spray, targeting only the unwanted plants to support a thriving garden ecosystem.

Regulatory and Usage Guidelines

When considering pelargonic acid for weed control, it’s essential to adhere to regulatory frameworks and follow best practices for application. These measures ensure safety and effectiveness in managing unwanted vegetation.

Product Labelling and Legislation

Legislative Compliance: Before using pelargonic acid as a herbicide for controlling weeds, verify its approval by the Environmental Protection Agency (EPA) or relevant local body. Product labelling will provide critical information, including approved uses and any restrictions. Legislation concerning pelargonic acid may vary by region, reflecting environmental protection priorities.

  • Check for an EPA registration number.
  • Follow directions for use specified on the label.

Safety Notices: Always read the label for safety advice, such as necessary protective gear when handling the product. Labels will also detail how to safely store and dispose of pelargonic acid to prevent harm to yourself or the environment.

Application Best Practices

Technique: Apply pelargonic acid directly onto the weeds you wish to eliminate. It’s effective against many weeds, including deep-rooted species, and works on contact, so ensure thorough coverage. Remember, pelargonic acid is a non-selective herbicide and will affect all plants it contacts.

  • Apply during dry weather for optimal effectiveness.
  • Avoid spraying on or near desired plants, canes, or crops.

Environmentally Considerate Application:

  • Pelargonic acid is a fatty acid and considered more environmentally friendly than some synthetic chemicals. However, it is still important to prevent runoff to water bodies.
  • Avoid applications during windy conditions to minimise drift to non-target areas.

By following these guidelines, you can use pelargonic acid effectively for weed management while remaining responsible and compliant with the law.

Understanding User Needs and Preferences

When seeking weed control solutions like those involving pelargonic acid, it’s essential you consider the balance between ease of use and effectiveness. Your preferences will ultimately guide your choice of weed management strategy.

Ease of Use

Sprayer: You’ll find that using a sprayer with pelargonic acid for weed control is straightforward. Ensure your sprayer is calibrated correctly for even distribution, since inconsistency could lead to suboptimal results. Ease of use is enhanced with sprayers designed for practicality—look for features such as adjustable nozzles and comfortable grips.

Weed Burners: For something more tactile, weed burners might be an alternative you wish to explore. While handling a weed burner, your safety is paramount—always read the manufacturer’s instructions. However, bear in mind that these tools require precautions due to their use of direct flame.

Electric Weed Killers: Electric weed killers offer a convenient, no-chemical method of weed control. The best models are user-friendly with ergonomic designs, reducing strain during extended use. Keep an eye out for options that prioritise ease of use with features such as extendable handles or wheels.

Effectiveness and Results

When you apply pelargonic acid, you expect it to perform efficiently against weeds. Studies have indicated that pelargonic acid is effective in killing weeds, though results can be influenced by application techniques and environmental conditions.

Sprayer: An even application with your sprayer can result in more comprehensive weed coverage, hence a greater weed kill rate. Matching the sprayer to your garden size and weed density is key—the right tool ensures that the product is dispersed effectively.

Weed Burners and Electric Weed Killers: Physical weed control methods like burners and electric killers may offer immediate results. However, unlike pelargonic acid, which works on the surface level of the plant, these tools might not affect the root system, which can allow for weed regrowth.

Ingested Methods: While pelargonic acid is applied externally, be aware that ingested weed killers have different application methods and precautions. Ensure that you follow product guidelines meticulously to achieve desired results without harming desirable plants or the environment.

Addressing Common Concerns

Pelargonic acid is recognised for its effectiveness against a variety of weeds, yet it is important to consider factors such as resistance and the availability of alternative weed control options.

Resistance and Adaptation

When you employ pelargonic acid as a herbicide, the concern of resistance, as is noted with substances like glyphosate, might cross your mind. Fortunately, pelargonic acid functions as a contact herbicide, causing immediate damage to plant tissues, which renders resistance development less likely. That said, it’s not to say weed populations cannot adapt; therefore, it’s recommended to use herbicides in conjunction with other weed management practices.

Alternative Control Options

While pelargonic acid is an effective solution, it’s not the sole option. You might explore environmentally friendly alternatives, such as bicarbonate of soda, which is known for its weed-suppressing qualities, particularly against pests like bindweed. It’s critical, however, to assess the situation of your canes or desired plants as such alternatives may affect soil pH levels. Another option is bleach, yet its application should be cautious, ensuring it doesn’t come into contact with desirable plants or soil due to its non-selective and potentially harmful nature.

Frequently Asked Questions

Pelargonic acid is an active ingredient in various herbicidal products known for its efficacy in weed control, and its non-selective nature indicates it will affect most vegetation it contacts. Let’s address some common queries regarding its use.

How quickly does pelargonic acid act on weed elimination?

Pelargonic acid acts rapidly, typically causing visible wilting and browning of weed foliage within hours of application, as demonstrated in research on controlling both broadleaf and grass weeds.

Is pelargonic acid a viable option for clearing lawns of unwanted plants?

Due to its non-selective characteristics, pelargonic acid can kill lawn grasses along with weeds. It’s most suited for spot treatment rather than as a blanket lawn weedkiller.

In terms of safety, how does pelargonic acid compare to other herbicides?

Pelargonic acid is considered to have a favourable safety profile as it is a naturally occurring fatty acid. Unlike some synthetic herbicides, it is biodegradable and generally poses minimal risk to humans and animals when used as directed.

Can pelargonic acid be considered a systemic weedkiller like glyphosate?

Pelargonic acid is not systemic. It is a contact herbicide, meaning it only affects the plant parts it comes into contact with. Systemic herbicides like glyphosate are absorbed and move within the plant to target multiple growth processes.

What are the environmental impacts of using pelargonic acid for weed control?

Pelargonic acid degrades quickly in the environment and is less likely to have long-term residual effects, making it a more environmentally friendly option for weed control compared to some persistent herbicides.

Does pelargonic acid have selective herbicidal properties, or does it affect all vegetation?

Pelargonic acid is a non-selective herbicide that will damage or kill most plants it contacts. Its use requires careful application to avoid harming desired vegetation.

About the author 


Hey there, I am founder and editor in chief here at Good Grow. I guess I've always known I was going to be a gardener. I'm on a mission to share my UK based weed control & lawn care tips with you all. If you have any queries please post in the comments below.

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