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Homemade Insecticidal Soap Spray for Plants

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3 Homemade Insecticidal Soap Sprays for Plants

So you’ve spent weeks carefully tending to your garden, and now aphids and other sap-sucking pests are appearing on your plants. Before you think of spending on commercial products, try a homemade insecticidal soap spray instead.

It’s a natural, organic option to get rid of small, soft-bodied plant pests. Moreover, soap spray insecticides are gentle, safe, and highly effective.

Best of all, you can feel good about avoiding harsh pesticides while still protecting your garden.

What is Insecticidal Soap?

The remedy is basically a natural pest control method using potassium salts of fatty acids to kill small, soft-bodied insects and related pests.

The soap suffocates the pests by clogging their breathing holes and damaging their cell membranes. It works on contact, so you have to spray the critters directly to be effective.

The good news is that it’s non-toxic to humans and breaks down quickly in the environment.

How Does It Work?

It works by penetrating the insect’s exoskeleton and disrupting cellular membranes. The soap’s fatty acids break down the insects’ protective wax and oil coatings, causing them to dehydrate and die.

It works on contact alone, so repeated applications may be needed.

How to Make Natural Insecticidal Soaps

Below are two simple recipes for insecticidal soap that you can use in your garden and home.

They make great homemade bug spray for your plants. You can also use them on hard surfaces, like killing ants on the floor or kitchen counter.

Recipe One

To make a natural plant insecticide soap at home, you’ll need organic liquid soap, tap water, and vegetable oil.

Use a mild dish soap, preferably a natural, eco-friendly formula without dyes or fragrances. Castile soap made of plant-based oils works great.

For the oil, any organic cooking oil will work—canola, soybean, or cottonseed oil. But avoid olive oil, which can block the pores on the leaves [1].

To make the spray:

  1. Mix 2.5 tablespoons of organic liquid soap and 2.5 tablespoons of vegetable oil of your choice. Shake or stir well to combine.
  2. Add the mixture to 1 gallon of water. Shake or stir again to mix thoroughly.
  3. Next, pour it into a spray bottle and label it clearly. Shake before each use.
  4. Finally, thoroughly spray the leaves of your plants, especially the undersides.

This natural, DIY insecticide is a safe, organic option to control many common soft-bodied garden pests. But be sure to spot-test a few leaves first to check for any damage before spraying the entire plant.

Recipe Two

For this recipe, you’ll need just two ingredients:

  • 4 tablespoons of organic liquid soap (some people use Dawn dish soap, but we prefer not to).
  • 1 gallon of water

Now mix the soap and water thoroughly in a spray bottle or pump sprayer. Shake before each use to combine.

That’s it! The soap will naturally smother soft-bodied insects like aphids, spider mites, mealybugs, and whiteflies. It’s also a mild liquid soap spray for your plants. However, still test on a leaf first to check for leaf burn (some plants are very delicate), then spray your plants thoroughly.

This gentle, non-toxic spray works great for indoor houseplants and outdoor gardens.

Recipe Three

This one has three ingredients: castile soap, neem oil, and water.

Make a DIY neem oil and castile soap insecticide by combining one tablespoon of neem oil with one tablespoon of organic castile soap in a liter of water. Dr. Bronner’s liquid castile soap is a good brand.

Shake well and apply to your plants as you would the other recipes.

How to Use Soap Sprays

Once your insecticidal soap spray is mixed, it’s time to use it. Apply it when insects or their damage are first noticed. For the best results:

Spray plants in the evening or on an overcast day when the sun is not intense. The direct sun can burn wet leaves, even with a gentle soap spray.

Spray the posts directly. Also, completely coat the tops and undersides of leaves, as well as any stems.

Pay extra attention to where you see insects or insect damage. Spray until the plant is dripping for maximum coverage.

This will target mature insects, larvae, and nymphs, but it will not harm tough eggs.

How Often to Use

To keep your plants pest-free, it’s best to spray them regularly with homemade insecticidal soap.

As a general rule of thumb, you should spray every 14 days as a preventative measure. More frequent spraying, around every 4 days, may be needed if you’re trying to get rid of an active infestation.

During the peak growing season in spring and summer, it’s a good idea to spray once a week or every other week. This will help deter common garden pests.

Types of Insects and Related Pests That Insecticidal Soap Controls

Insecticidal soap spray controls several common plant pests [2]. The soap solution is most effective against:

  • Aphids
  • Sawfly larvae (rose and pear slugs)
  • Mealybugs
  • Mites (spider mites, broad mites, rust mites, etc.)
  • Young scale
  • Leafhoppers
  • Whiteflies
  • Psyllids
  • Thrips
  • Leaf miners
  • Ants
  • Earwigs

Commercial Products

If you can be bothered to make DIY insecticidal soap, otherwise called horticultural soap, you can purchase popular plant insecticide soaps that other gardeners are using.

Below are two good options:

Bonide Brand

The ready-to-use insecticidal soap can be applied indoors and outdoors to kill insects on contact. It is powered only by potassium fatty acids (derived from plants).

Bonide Insecticidal RTU Soap also does not remain in the environment. This means you can apply it to your crops as often as desired (either weekly or biweekly).

You can also apply it to edible plants up until harvest day.

Monterey Brand

Monterey Insecticidal Soap is an all-natural insecticide and fungicide that can help get rid of common garden pests and diseases.

This spray works on contact, so for the best results, spray when insects are most active. It also prevents and controls powdery mildew.


The above are our insecticidal soap spray recipes to help you combat common garden pests without the use of harsh chemicals.

The best part is that you can feel good knowing exactly what’s in the spray and that it’s safe for the environment, kids, and pets. So grab your spray bottle and get mixing; your garden will thank you.

Sasha Brown

Sasha Brown is a blogger and lover of all things natural.

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