Spraying for Garden Pests

It’s that time of year again! Now that our gardens are in full swing, the bugs are relishing the menu. Insecticidal soap, made from Dr. Bronner’s Pure Castile Soap works very well in ridding your plants of these pesky pests.


  • Spray bottle
  • Castile soap (any variety – but there is a chance you’ll taste the essential oils, so you may want to go with the unscented Baby Mild or Peppermint)
  • Cayenne pepper, cinnamon, or powdered garlic
  • Water

77 thoughts on “Spraying for Garden Pests

  1. Do any of your products work on fleas? Either on the dog itself, or sprayed in the house or outside? There are so few options other than actual poisons. Diatomaceous earth can help, but who wants it sprinkled all over their house!

    • Hi Mary – Our Pure Castile soaps work very well on getting rid of fleas on animals. The peppermint is usually my go-to because of the naturally deterring effect of peppermint, but any of them will work. Check out my post on washing dogs with castile, http://www.lisabronner.com/washing-the-dog-with-dr-bronners/. I don’t know that the soap will effectively eliminate fleas from carpets and other soft furnishings where they like to live around the house. Even with a carpet cleaner, it would be tough to reach all the nooks with enough heat and soap to kill any fleas and eggs. If you can wash dog beds and blankets in castile soap, that’s a great start. This post may help you with that, http://www.lisabronner.com/dust-mites-and-castile-soap/. Hope this helps!

    • Hi there – The soap stops insects by dissolving their exoskeletons. Larvae and caterpillars don’t have this, but I still think they might not like the soap. I can’t give you a definitive answer.

      Can any other readers weigh in here?

  2. I discovered aphids in my garden several days ago. I tried just blasting them with some water but that didn’t seem to help. After doing this for a couple of days and watching the population just increasing, I did some research and discovered the relationship between those aphids and ants. So I began sprinkling DE on my garden and again water blasting the ants for a couple of days. Again I found the aphid population continuing to increase and spreading to other plants. Thank goodness I found a recipe on YouTube that said to use a 1 gallon garden sprayer with 2 1/2 to 5 Tbsp of Dr. Bronner’s castile soap. I went with the lower soap amount and sprayed my plants. The next day, today, I found more than half of the aphid population gone. We got 2 inches of rain last night so I sprayed again today. I am thinking of adding the cayenne pepper or garlic to keep those leaf eaters off too. Thanks for all you do!

  3. We use Castile soap in a foaming dispenser for hand washing. Recently we’ve been invaded by Japanese beetles. I put about an inch of foam in the bottom of a jar and took it out to the garden and knocked them into it. They were dead before the sunk out of sight. I wondered if mixing into a spray and dispensing onto the plants would be effective? Also I wondered if I could spray this on wasp nests that are built at the peak of my house? And if it would damage my vinyl siding? Any help would be appreciated.

    • Hi Ron – Wow! Great testimonial! A spray of the soap and water would kill japanese beetles on contact, but the residue of it is not an effective deterrent. In other words, it only works when wet.

      Regarding the wasps, I have never tried going after wasps with the soap. Theoretically, it would probably stop hurt them, but again, it would only work when wet, and it would have to be a direct hit. A mist around them wouldn’t be effective. My concern is that in the process of trying to hit them, you might get them mad and riled up, and this method could seriously backfire.

      It wouldn’t damage your vinyl siding, though.

  4. Aphids are natures cleanup crew. An indicator that something is out of balance. Typically using liquid fertilizers like Miracle Grow will increase aphid populations. The plants are under some sort of stress usually an excess of nitrogen fertilizer. A critical part of controlling aphids it to also control ants. They will protect the aphids to keep those sugars coming. Aphids excrete sugars.

    3 TBS soap to G of water add 1 TBS of 70% alcohol.

    Better yet 2TBS Peppermint soap and 1TBS of vegetable oil.

    Recipes from my years as horticulture director for The Mirage Hotel

    • Great info! Thank you for sharing!

      Which recipe would you suggest if combining all three…Castile soap, a vegetable oil and alcohol?

      What alcohol is safe and cost effective?

  5. Will this recipe work on apple trees and apples with out leaving a taste or health effects, but still protect the apples from bugs that seem to bore into the apples this time of year.

    • Hi Bob – The soap solution would have to come into contact with the insects when it is wet. The residue does nothing. So, if you have an infestation where you can see the bugs, the soap will help. If the damage is being done when your back is turned, it won’t. I don’t know what types of pests affect apples, but the soap solution works for bugs with exoskeletons. I don’t know that it would work on any kind of worm or caterpillar. As far as health goes, it is completely healthy and I do not think it would affect the taste of the apples, but perhaps use one of the food-ish scents just in case, such as almond.

  6. The recipe portion of the page seems to have disappeared – using Chrome browser. This is true for the household cleaning spray page as well. Is it just for me, or is there something gone weird with the page? I can see the post title and date, then down thru the supplies you need, then it’s just blank until the Comments.

    • Hi Jac – There’s actually a video inserted there in which I shared the recipe and I didn’t have the recipe typed out, for some reason. Here it is:
      In a spray bottle combine 1 quart water and 1 Tablespoon soap. This is all I do, but if you want to be fancier you can throw in a couple extras:
      Optional add-ins are cayenne pepper, garlic powder or cinnamon which can all provide additional deterrence. You can also add 1 Tbsp. of vegetable oil so that the solution doesn’t evaporate immediately off the plant, but with the oil, the solution will go rancid more quickly.

    • Thanks, Lisa! Perfect timing for me here in California. Many buggy plants right now. I sure hope it rains soon. I’m glad I rediscovered Dr Bronnee’s. I am SO enjoying all your products!

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