5 Of The Best Organic Herbicide Options You Should Be Using Instead!

Organic herbicides are made from natural ingredients and are far less harmful to the environment than chemical herbicides. Many gardeners are switching to organic products to control unwanted weeds. However, there are still relatively few commercial organic weeds killers on the market.

Weed Killer

Organic herbicide products, like Avenger, WeedZap, Weed Pharm, AllDown, and GreenMatch EX, are effective on food and non-food crops. They disturb plant tissues they come into contact with by removing the waxy cuticle or damaging cell walls, thereby causing the plant to dry out or stop growing.

The products featured in this article are fantastic alternatives to toxic chemical herbicides, like the notorious RoundUp. Here, we discuss what makes them work, how to use them, and which weeds they can control.

1. Avenger Weed Killer

Alternative toReward
Active Ingredientsd-limonene
ActionNon-selective post-emergent contact herbicide
Suitable for use onBroadleaf weeds and grasses

Avenger Weed Killer is a USDA Organic Certified herbicide for agriculture and gardening. The Organic Materials Review Institute (OMRI), a US-based non-profit organization that independently reviews organic products, has approved it.

It was also the first organic herbicide in the US to be approved by the Environmental Protection Agency (EPA). Avenger is one of the most trusted organic herbicide products on the market. It is non-toxic, biodegradable, and safe for the environment, wildlife, pets, and children.

How Does It Work?

The active ingredient in Avenger is d-limonene, a citrus oil that is derived from orange peel. D-limonene is a powerful degreasing agent. All plants have a waxy cuticle that prevents them from losing too much moisture. The d-limonene destroys this waxy layer, causing weeds to desiccate and die.

How Long It Takes To Work

It is extremely fast-acting, and one should see results as soon as an hour post-application. It is even faster-acting than RoundUp!

Guidelines For Use

Avenger is a contact herbicide, meaning that it acts as soon as it comes into contact with plant tissues. It is a non-selective herbicide, so it works on a wide range of plants, not just certain weeds. Do not let it touch desirable plants.

Avenger is a post-emergent herbicide. This means that it works on weeds that have already started growing instead of preventing weed seeds from germinating. It is effective on most grasses and broadleaved weeds.

This product is much more effective in eliminating small annual weeds that are less than 6 inches tall than larger perennial weeds. On annual and perennial weeds larger than 6 inches, or species that are difficult to kill, one should use a higher concentration of Avenger.

Avenger is most effective and works fastest when applied in hot, humid conditions. However, you can use it in overcast weather. Do not apply Avenger in the rain or if rain is forecast! Water will rinse the product off the weeds, reducing its efficacy.

This product is excellent to use on the edges of lawns. It comes in two forms – as a concentrate and as a ready-to-use spray. The concentrate is better for large scale agricultural use, while the spray is great for use in gardens.

Avenger Organics, Avenger Weed Killer Concentrate, for Organic Gardening, 32 oz
  • Fast Acting - visible results in less than 2 hours
  • Made from oranges, pleasant citrus aroma
  • Non-toxic formulation can be used around people, pets and wildlife

Last update on 2024-06-13 / Affiliate links / Images from Amazon Product Advertising API

2. WeedZap

Alternative toScythe
Active IngredientsClove oil and cinnamon oil
ActionNon-selective post-emergent contact herbicide
Suitable for use onBroadleaf weeds and grasses

WeedZap is an OMRI listed organic contact herbicide. While it is not yet EPA-approved, it has been proven to be non-toxic and environmentally safe. It is suitable for organic production as it is 100% biodegradable.

How Does It Work?

The active ingredients in WeedZap are clove oil (45%) and cinnamon oil (45%). These oils coat the surface of weeds and are then absorbed into the plant cells. The active ingredients harm the cell structure, causing weeds to wither and die.

How Long It Takes To Work

WeedZap is not as fast-acting as Avenger. Results are visible after 6 hours, and it kills the majority of weeds within 12 hours. Some hardy perennial weeds may take a little longer to die. The product has a prolonged residual effect.

Guidelines For Use

As a contact herbicide, WeedZap must be sprayed onto the foliage. It is effective against most broadleaf weeds and weed grasses when applied correctly. The spray must coat the whole surface of the plant.

WeedZap is a post-emergent herbicide. It is best for killing weeds that are less than 6 inches tall. It is a non-selective herbicide, so one must be careful not to get the product on any desirable plants. However, it will not harm any larger plants with woody stems.

Because the active ingredients catalyze a burndown process within the weeds, this product is most effective when applied in sunny, open areas. It does not work as well in shady areas of the garden.

The product is sold as a liquid concentrate. Before use, it has to be diluted in water according to the label instructions.

Even though this is an organic product, one must still wear protective gear to prevent contact with eyes and skin. Wear a long-sleeved shirt and pants, closed shoes, waterproof gloves, and protective eyewear.

WeedZap is proven to be effective against most common weeds, including:

  • Bermuda grass
  • Canary grass
  • Dandelion
  • Chickweed
  • Knapweed
  • Wild mustard
  • Wood sorrel
  • Star thistle
  • Sow thistle

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3. Weed Pharm

Alternative toTenacity
Active IngredientsAcetic acid
ActionNon-selective contact herbicide
Suitable for use onAnnual and perennial weeds and grasses

Weed Pharm is an organic herbicide that meets the USDA Natural Organic Program standards. Weed Pharm is approved by the Washington State Department of Agriculture as well as the State of California Department of Pesticide Regulation.

This product is non-toxic and safe for pets and children. It is approved by OMRI and is registered with the US EPA. Weed Pharm is safe for use in the garden or on agricultural crops.

How Does It Work?

The active ingredient in Weed Pharm is acetic acid or vinegar. However, this stuff is not the same as the vinegar you keep in your pantry. Weed Pharm contains 200-grain vinegar, which is much, much stronger. Regular household vinegar does not work to kill weeds.

Acetic acid dissolves plants’ waxy cuticle, causing them to dry out and die. After acting to destroy weeds, acetic acid biodegrades. It does not bioaccumulate or affect the soil adversely.

Time It Takes To Work

Weed Pharm is extremely fast-acting. It should kill 90% of weeds within 24 hours from application.

The acetic acid breaks down very quickly, so has no residual effects in suppressing weeds. For the best results, one should reapply it every two weeks.

Guidelines For Use

Like Weedzap and Avenger, Weed Pharm is a contact herbicide that kills any plants it touches. It must be sprayed onto weed foliage so that plants are thoroughly coated. Weed Pharm does not need to be diluted before use.

As this is a post-emergent herbicide, it works on weeds that are already actively growing. It is most effective when plants are still very small, so monitor the weeds and treat them within 2 weeks of germination.

For older, established patches of weeds, first, use a lawnmower to cut them 4 to 6 inches tall. Then apply the product. For hardy perennial weeds, reapplication is necessary every 2 weeks.

Weed Pharm is a non-selective herbicide. It can be used as a spot treatment or broadcast with a sprayer, but whatever application method you use, you must ensure that desirable plants are not sprayed.

When broadcasting with a sprayer, it must be applied very carefully using a shielded or hooded sprayer. This will prevent the Weed Pharm from harming crops or ornamental plants. Weed Pharm is most effective on weeds when applied on hot, sunny days.

Safety Precautions

Weed Pharm is a strong product, and it is toxic to fish and aquatic organisms because it changes water pH drastically. It cannot be applied near water sources.

It is also toxic to birds. Do not apply this herbicide to areas that birds actively visit. The product residue and spray drift are very dangerous to them. Do not spray on windy days.

One should wear protective clothing when working with Weed Pharm, as it is corrosive and can cause severe burns to skin and eyes. It is critical to wear protective eyewear, waterproof gloves, long-sleeved pants and shirt, and closed shoes.

Weed Pharm is ideal to use for controlling weeds on paved or gravel sidewalks and patios.

It is proven to be effective against the following weeds:

  • Broadleaf plantain
  • Ground ivy
  • Cutleaf evening primrose
  • Pigweed
  • Amaranth
  • Crabgrass (recently germinated)

This product does not work to control weeds with very deep taproots, like dandelion and thistle. It will kill the foliage, but the weeds will reshoot from the roots.

4. AllDown

Alternative toRoundUp
Active IngredientsAcetic acid, citric acid, and garlic extract
ActionNon-selective post-emergent contact herbicide
Suitable for use onAnnual and perennial broadleaf weeds and grasses

AllDown was developed in 2002 in Oregon and is a trusted brand of organic herbicide. It is listed with OMRI and is registered with the US EPA.

AllDown is available as a ready-to-use spray for use in residential gardens and as a concentrate for larger-scale agricultural applications.

How Does It Work?

The active ingredients in AllDown are acetic acid (23%) and citric acid (14%). These act to break down plants waxy cuticle, causing them to dry out and die.

Time It Takes To Work

AllDown is a fast-acting herbicide. You should notice results within 24 hours of treatment. Because the active ingredients biodegrade very quickly, reapplication once every 2 weeks is required to ensure effective long-term weed control.

Guidelines For Use

As this is a non-selective contact herbicide, it will harm any plant tissue that it comes into contact with. It is very important to avoid getting AllDown on desirable plants.

It is a post-emergent herbicide that is most effective on young weeds that are between 3 and 5 inches tall. AllDown can be used to burndown larger annual and perennial weeds, but this requires reapplication every 2 weeks.

The optimal time of year to treat weeds with AllDown is at the start of spring, when weeds are just starting to grow. The treatment is more effective on hot, sunny days. Do not spray weeds if there is rainfall predicted, as the rain will wash it off the plants.

To prevent spray drift, use AllDown on a day without wind. This product can contaminate water bodies, so do not apply it to areas where it can runoff into stormwater drains, drainage ditches, gutters, ponds, or dams.

This product is wonderful for use along fence lines, on patios, driveways, and pathways. It can also be used around fruit trees and on weeds and grasses in vegetable gardens.

AllDown is proven to work against the following broadleaf weeds and grasses:

  • Quack grass
  • Bermuda grass
  • Rye grass
  • Crabgrass
  • Wild carrot
  • Dandelion
  • Burdock
  • Cinquefoil
  • Stinkweed
  • Portulaca
  • Mustard
  • Chickweed
AllDown Summerset Concentrated Herbicide (1 Gallon)
  • OMRI Listed - Concentrated Organic Weed-Killer, Non-Selective Broadleaf and...
  • For Residential Use in Organic Gardening
  • Environmentally and Pet Friendly

Last update on 2024-06-13 / Affiliate links / Images from Amazon Product Advertising API

5. GreenMatch EX

Alternative toReward
Active IngredientsLemongrass oil
ActionNon-selective post-emergent contact herbicide
Suitable for use onBroadleaf weeds and grasses

GreenMatch EX is an organically certified herbicide that is OMRI listed and registered with the Washington State Department of Agriculture’s Organic Food Program.

How Does It Work?

GreenMatch EX’s primary active ingredient is lemongrass essential oil. It is phytotoxic and interferes with plants’ ability to photosynthesize.

Time It Takes To Work

GreenMatch EX is a fast-acting herbicide. You can see leaves starting to wilt by 6 hours after treatment.

Guidelines For Use

This product needs to be diluted at 10-15% before application. An application rate of 100 gallons per acre is proven to be most effective for controlling broadleaf weeds and grasses.

It is a post-emergent herbicide that works best on young weeds. However, research is currently being done on lemongrass oil as a pre-emergent herbicide.

As a contact herbicide, it must be sprayed onto weeds to kill them. It is critical to coat the weeds thoroughly to ensure effectiveness. This product is non-selective, so precautions must be taken to only apply it to weeds and not desirable plants.

GreenMatch EX’s efficacy is also improved by mixing it with a surfactant, like Nu Film. This helps it stick to the plant better.

GreenMatch EX is excellent for controlling the following weeds:

  • Shepherd’s purse
  • Fleabane
  • Bluegrass
  • Crabgrass
  • Sowthistle
  • Clover
  • Mustard
  • London rocket


Why keep using toxic, chemical herbicides in the garden when there are so many organic alternatives to help you battle weeds. These are widely available online or from garden supply stores.


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    Author, blogger, podcaster, homesteading and permaculture enthusiast. I have a passion for sharing what I learn and helping others on their journey. If you're looking for me, you'll usually find me in the garden.

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