DIY Homemade Weed Killer (Also Good For Ants!) With Secret Ingredient

Today’s chemist solution is an easy homemade weed killer with a secret ingredient that may surprise you! I have been testing out this homemade weed killer for awhile now and I am so impressed with how well it works. I wanted to create something that was easy to put together, but also fast acting! Weed killer from the store can be expensive, not to mention it is full of so many harmful chemicals. I hate spraying that stuff around my house with Ruger around. He always gets curious and sniffs everything! The secret ingredient in this really makes it work fast! In fact, I applied this again a few days ago and shortly after it rained! I was afraid it would wash away the spray, but it had already starting working.


  • 3 cups distilled white vinegar
  • 3/4 cup regular table salt
  • 2 tsp blue dawn dish soap (works best, but can use others)
  • 3 tsp liquid arthritis rub (seriously!!! Make to sure to read why here )


In a spray bottle, add the salt, dish soap, vinegar and capsicum type rub (found in grocery stores for only a few dollars, see picture below). Shake it up until well mixed. Apply directly to the leaves of the weed. It starts working almost immediately, by 24 hours the weed is almost completely gone. It will continue to die and wither away! **This is not recommended on weeds in grass, it can harm grass. Always make sure to spray the leaves of the weed directly, it should never actually touch soil. Use with caution around flower beds, if you get water that washes downhill, try not to spray weeds uphill from flowers in case it rolls down. Also, this is a very diluted saline solution, it doesn't harm animals or leaves lasting effects on soil (it shouldn't need to be sprayed on soil).

About Chemistry Behind This Solution: There are so many awesome things going on in this solution! Chemically, vinegar (acetic acid) is a strong acid which has the ability to kill or burn the leaves of weeds. Add in the salt (sodium chloride) which catalyzes the reaction of the vinegar. The dish soap has always been a great weed killer. It creates a nice spray too. Lastly, the secret ingredient: arthritis rub which contains capsicum (from peppers) and methyl salicylate (from wintergreen). What does capsicum and methyl salicylate do? Full details plus many important tips on use here. Make sure to check the blog post below to read our list of FAQs :)

Alexis @ Chemistry Cachet
Want more details about this and other DIY projects? Check out my blog post!
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  • Kyb5723671 Kyb5723671 on Jun 17, 2018

    Will this kill grass?

  • Elaine Elaine on Jul 01, 2018

    To kill ants, do you spray them directly or can you spray an area where they crawl?

  • Helen Helen on May 22, 2021

    will this weed killer hurt the birds I will be spraying right under their feeder

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