Does Ammonia Kill Weeds? Process Explained

Weeds are a nuisance that creates an eyesore. They have the ability to grow in the most random places, be that patios, driveways, in the middle of a lush lawn, or among a thriving flower bed.

There are many conversations about the merits of ammonia to kill weeds, its efficiency, and safety.

Ammonia is toxic and potentially harmful. However, used carefully in exact quantities, it efficiently kills weeds at the source, preventing them from returning the following season.

In doing so, due to its non-selective nature, ammonia might also kill healthy plants and grass and cause long-term damage to the soil.

What is Ammonia

Ammonia is a colorless, reactive gas that dissolves in water.

It is a compound of nitrogen and hydrogen – NH3 that occurs naturally in air, soil, water, plants, and animals. It carries a strong, urine-like odor.

It has many uses, the primary one being fertilizer. Up to 90% of all of the ammonia globally produced is used this way; this seems counter-productive for weed-killing.

Ammonia is the main constituent of many household cleaning products and has industrial/manufacturing uses. It is also prevalent in water and wastewater treatments.

How Ammonia Kills Weeds

When sprayed around a problematic area, ammonia solution either seeps through soil and attacks the roots or directly through the evident top growth. It attaches to cells and slowly clogs them, resulting in dehydration and slow death for the weed.

It might not be the quickest solution, but it is one of the most successful. The ammonia alters the pH of the soil, thus preventing future weed growth.

Reasons to Use Ammonia to Kill Weeds

A Safer Alternative to Herbicides

Herbicides are substances toxic to plants used to destroy unwanted vegetation. They are chemical compounds available in selective and non-selective products that kill specific plants or everything growing in the area.

Reducing the use of herbicides is better for the environment.

Ammonia is a natural product, and therefore, safer when used with caution.

Herbicides Can be a Danger to Humans Unless Used Responsibly

Inhalation of certain herbicides - paraquat in particular - over prolonged periods may cause respiratory tract issues, nose bleeds, and mild to lethal cases of poisoning.

Ammonia contains toxins but, in the correct proportions, it is safer for children and pets. For greater peace of mind, keep them away from the area until the solution has thoroughly soaked in.

Herbicides Can Create Adverse Environmental Conditions

Although the safest option, extensive use of herbicides causes potential risks for the environment. With fewer nesting sites for birds and a disruption of animals otherwise abundant food sources, many species are endangered.

Ammonia Prevents Seasonal Regrowth

Liberal use of ammonia spray not only kills specific weeds but also destroys root systems. They won't return in the same spot the following season.

It is an Effective Weed Killer

It might not work as fast as other products, but ammonia works very effectively. Not only does it kill weed on the surface, but it also eradicates root systems.

Reasons Not to Use Ammonia as a Weed Killer

Ammonia is Non-selective

It doesn't just kill weeds; ammonia is indiscriminate and destroys all living plant life around it, including grass. Overuse alters the pH of the soil, making it difficult to grow plants in consecutive seasons.

It Smells

Ammonia emits a pungent smell due to its urea content. The fumes are reminiscent of stagnant urine.

There are Safer Solutions

If you're concerned about children or pets using the treated environment, there are several natural solutions to consider:

  • Corn gluten suffocates weeds at the source.
  • Acetic acid has excellent results above and below ground. It destroys leaf cuticles causing the entire weed to wither and die.
  • Natural herbicides are a solution made from plant extracts and essential oils. They pack a punch when applied topically, as and when weeds emerge.

It is Water-soluble

Once applied to soil in a garden, ammonia dissolves into the moisture. It enters the ecosystem, creating life-threatening issues for fish and other garden-dwelling creatures.

How to Kill Weeds with Ammonia

spraying weeds with ammonia

You need to mix the ammonia in exact quantities for the best results.

Gather the Necessary Equipment

  • bucket
  • stirring tool
  • funnel
  • spray bottle with adjustable nozzle

Safety Wear

Always use rubber gloves and wear long sleeves. Ammonia is an irritant that burns should it come into contact with skin.

A face mask and goggles are worth considering. The fumes produced by ammonia are toxic and lead to a burning sensation in the throat, nose, and chest.

Goggles protect eyes from damage if there is the remotest possibility of splashback.

Mix the Solution

Add 2/3 ammonia and 1/3 water to the bucket and mix thoroughly and decant into the spray bottle using the funnel. Ensure all items are well-washed in hot, soapy water before further use.

Kill the Weeds

Adjust the nozzle to 'jet'; spray the overgrowth of each weed, also aim towards the soil and roots. You should note some wilting almost immediately, although the best results will probably be the following day.

Spray carefully; remember, ammonia is non-selective and kills prized flowers and well-manicured lawns every bit as effectively as it destroys weeds.

Repeat this for every nuisance weed before disposing of the gloves and leftover solution.

Does Ammonia Kill All Weeds?

Ammonia is very effective against stubborn weeds where other products failed.

  • Crabgrass -Not only does it eradicate the weed, but it also prevents it from returning in consecutive seasons.
  • Dandelions - They are notoriously annoying weeds that appear anywhere, especially during spring. Ammonia eradicates them with one application.
  • Poison sumac is a dense, thick weed that responds well to ammonia treatment.
  • Common ragweed is especially troublesome to allergy sufferers. The ammonia solution wipes it out.
  • Ground ivy cannot survive after ammonia applications.

The high concentration of nitrogen in ammonia affects nutrient levels in the soil. It is often used in fertilizers to promote faster growth and give plants a healthy color.

Mixing ammonia with sulfates common in herbicides increases its strength. It is useful when removing the hardiest, tenacious weeds, such as clover.

However, combining products creates a toxic solution that is dangerous for the uninitiated to use. Either call a professional or buy a pre-prepared heavy-duty weed killer.

Overuse of ammonia causes a significant change in the pH level of the soil and surrounding areas. The ground becomes inhospitable, and unlikely to grow anything for many years.

Final Thoughts

Ammonia does kill weeds; in many cases, it is more effective than store-bought products.

However, it also destroys any other plant life that it contacts.

Ammonia is a successful topical weedkiller on driveways, sidewalks, and patios. It is effective for small areas of wasteland that have little footfall.

Gardens with children, pets, and luscious lawns are best suited to other natural or selective herbicides.

Annette Marsh
For the past twenty years, Annette has allocated much of her free time towards gardening and landscaping related tasks; Planting flowers and trees, weeding, pruning, mulching, mowing, constructing ponds and various other structures, as well as growing and maintaining a vegetable garden.

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