DIY Insecticidal Soap for Houseplants


Every winter spider mites seem to get worse on my indoor plants. However it’s easy and inexpensive to keep them at bay! You can make a simple insecticidal soap that will kill only soft-bodied insects such as spider mites, aphids, and mealybugs.

In my home, my Rubber and Arrowhead plants fall victim to spider mites. You can tell if you have spider mites because you’ll either see white puff ball looking spots on your plants, or if it’s really bad, you’ll see tiny webs too.


To make insecticidal soap, you will need:

  • Water
  • Soap
  • Clean spray bottle

The Water: Tap water is fine. If you have hard water you can use distilled water instead to prevent build up on plants

The Soap: What kills the spider mites is the animal or vegetable fat, which is found in soap. Detergent, including dish detergent will not work because it doesn’t have the fat. If you have bar soap, you can shave it with a cheese grater, then melt it in warm water that will be used for the bottle after it cools.

I use Dr. Bronner’s liquid Castile soap, which is all natural. I keep this soap around the house for a multitude of cleaning purposes.

You can purchase Dr. Bronners at a lot of places now, a pharmacy store, health food store, and maybe even some big box stores like Target. It comes in different sizes, including travel sizes and even in bulk to fill your own container, available in some stores. It comes in a variety of scented or non-scented. I have peppermint, which doesn’t seem to harm the plant. Plus, it freshens the air when I use it!

The Spray Bottle: Any spray bottle will work that has a fine mist. Just make sure there wasn’t anything in it beforehand that will harm the plants.

The Recipe

  • Mix 1 TBS of soap per 1 Quart of water

I spray the problematic areas about once or twice a week until I see that the spider mites are gone.


There are pre-made insecticidal soaps out there on the market, but you can make it yourself for less money or basically for free. Even if you need to purchase soap, you can likely use the rest of the soap for other purposes. I often keep old spray bottles from (natural) products  (counter cleaner, fabric freshener) and reuse them. These spray bottles always seem to be better quality than new ones I’ve bought before.

Some other ways I use castile soap:

  • Make a paste with baking soda to use to scrub the bathtub and sink. A little goes a long way. I spray the tub first with a bit of homemade vinegar cleaner, scrub with the paste, then rinse with water. Don’t use this method if you have anything other than a plastic tub.
  • Use 1/2 C  soap per 3 gallons of water to mop kitchen floors
  • Any reason you need soap to clean an item. For general cleaning 1/4 C of soap per quart of water.
  • I haven’t tried it yet, but I am going to try making a foam hand soap with it after I run out of what I have. You can’t use Dr. Bronners in a regular soap pump or it will clog it up.
  • Mix a tsp of soap with a 1/4 cup of baking soda, spread over the bottom of oven to clean it. Spray enough vinegar over the baking soda until the paste looks soaked, but not soppy. Allow to sit 30 minutes (it’ll fizz for a minute). Wipe/scrub clean.





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