Homemade Insecticidal Soap: How To Make DIY Recipe

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Home gardeners have long used homemade insecticidal soap for insect control and to kill harmful garden bugs on plants. Over a century ago, fish oil soap was a common solution.

“Natural control” of pests is not something new in today’s green, eco-friendly world.

Making Homemade Insecticidal Soap RecipePin

In this article, we’ll share with you various recipe for insecticidal soap diy.

What Makes Insecticidal Soaps Work

So, what is insecticidal soap?

Some people believe a pest control secret exists to mix a DIY insecticidal soap in water and spray a plant.



Somehow, this helps remove bugs from your garden. Nope! A good blast of water can wash bugs away.

The secret (if one exists) is in the “soap” used to make the “insect-killing soap.”

So, what kind of soap can you use to make insecticidal soap?

Use a true, safer soap, like Dr. Bonner’s Castile soap, and not a dish detergent or dish soap – more on recommended soaps later.

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Photo Credit: Instagram @wilcostores

The insect killer power comes from the potassium salts of fatty acids contained in the soap.

Maintaining healthy flowers, fruits, or vegetable plants means inspecting them frequently for disease or insect infestation. If not treated promptly, plant-eating insects can ruin a harvest or strip a floral plant of its blooms.

The fatty acids work effectively, killing soft-bodied insects like aphids, mealybugs, leaf-piercing spider mitesthrips, scale insects, and whiteflies.

Read more on How To Get Rid of Aphid Infestations.

These fatty acids dissolve or remove the garden insects’ cell membranes and their natural protective waxy coatings, causing death from excess water loss.

Potassium salts in the soaps are the most useful in making insecticidal sprays to control plant pests.

One of the most well-known potassium-based insecticidal soap spray products is Safer Insecticidal Soap, which controls many plant bug pests found on houseplants, vegetables, and fruit.

I like to use Neem oil for plants. Another favorite is Diatomaceous Earth. In Australia, they make white oil insecticides.

Advantages of Garden Horticultural Soap

  • When made and used correctly, organic insecticidal soap sprays are Eco-Friendly to people, plants, animals, and the environment.
  • Plants susceptible to damage from soap sprays include beans, impatiens, cucumbers, ferns, sweet peas, gardenias, cherries, crown of thorns, Japanese maple, and peas. 
  • No residual effect
  • Effective against mealybugs, aphids, spider mites, and thrips (soft-bodied insects) when coming in direct contact
  • Biodegradable and nontoxic (right soap required!)
  • Safe for beneficial insects, bees, etc
  • Perfect for organic gardening and OMRI listed.

How To Make Insecticidal Soap Spray & Recipe?

Though garden soaps are available to control insect pests, you can make your own insecticidal soap inexpensively.

Dishwashing detergent made for dishes may not work. The right soap is key.

The Materials

The Soap – You want the real thing, pure soap which includes the active ingredient of fatty acids – the bug dissolver! Try to get a liquid soap to make mixing easier.

Commercial insecticidal soaps are highly refined versions of liquid dish soap. While you could make your insecticidal soap mixture, there is a substantially increased risk of plant injury with them.

Spraying homemade aphid repellent on a hibiscus.Pin
Photo Credit: Instagram @alittlelesstoxic

Look for an all-natural pure soap, like Dr. Bronner’s Pure Castile Soap, found in many grocery stores or local natural foods markets.

The soap should have no synthetic chemicals, degreasers, or skin moisturizers. Experienced gardeners also recommend Naphtha soap.

The Water – Use Pure Water. Distilled is good. If your tap water is good, use it, but if you have hard water, use bottled water instead.

Tap water is okay to use, but if you have hard water, you may want to substitute bottled water to avoid any soap scum buildup on foliage.

The Sprayer – A clean spray bottle (1 quart) or a garden sprayer will work. It really depends on how much you need to apply. DO NOT USE a weed-killer sprayer!

The Insecticidal Soap Mix:

Aim for 2% soap solution:

For a 1 Gallon Solution:

  • Mix in 1 gallon of water 5 tablespoons of liquid soap

For a 1 Quart Solution:

  • Mix in 1 quart of water 1 tablespoon of soap

Shake well!

Insecticidal soap recipe Variations

You’ll always find variations in any homemade insecticidal soap recipe or home-brewed formulas calling for more or less of some component.

Two consistent fundamentals in any of the various home-brewed insecticide formulas: stinky or hot-tasting ingredients make the best insecticidal soap additions.

Cayenne pepper, red pepper, garlic, powerful herbs and extracts, cider vinegar, and cooking oil.

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Photo Credit: Instagram @skogsskimmer

No “set formulas” exist. This is all trial and error for the insecticidal soap ingredients. What works for one may not work for someone else.

The rates below are all for 1 gallon of insecticidal soap spray recipe mix:

The Bug Chaser: Garlic or Pepper – Add 1 teaspoon of garlic and/or ground red pepper.

Powdery Mildew: Vinegar – 1 Teaspoon of cider vinegar

Make Spray Stick Longer: Cooking Oil – Add two tablespoons of light vegetable oil – corn, olive, grapeseed, canola, or safflower.

This diy insecticidal soap recipe mixture kills aphids, beetles, caterpillars, crickets, earwigs, lace bugs, leafhoppers, mealybugs, mites, plant bugs, scale crawlers, thrips, and whiteflies. 

More On How To Kill Aphids with Soapy Water

Learn and Observe

A Word Of Caution for garden pest control: Learn, Observe, and Always Test!

Some spays can do some serious damage to sensitive plant foliage. Always do a test spray in a small area of plants.

If the spray is too strong – dilute.

Try reducing the mix rate to a 1% solution if the soap insecticide recipe concentrate is too harsh.

If you read the label, most commercial insecticidal soap sprays come in a 1% solution.

However, remember a diluted solution may be easier on the plants but less effective.

While outdoors, look for plants not bothered by insects… even nearby weeds. It’s a non-toxic mixture, meaning it can be safely used even on your vegetable garden plants up until the day of harvest. 

You never know… blending some up to make some type of spray could be the new ingredient you’ve been looking for.

How To Tips On Applying Insecticide Soap

  • Before spraying, make sure to test the soap solution rate – see above.
  • Check the weather… Don’t spray on rainy days.
  • For best results, apply spray early in the day before 9:00 am or late in the afternoon after 5:00 pm. This allows the spray material to be more effective by staying wet longer on the plant.
  • Shake well to keep the spray solution mixed and agitated before applying. Keep shaking as needed. If the solution sits, agitate before spraying.
  • When applying a pesticide spray, remember the spray is not residual. The soap spray must cover and wet the pest, not just put a spray drop on the foliage.
  • Take the time to completely cover the tops, underside of the leaf, and stems with the spray mixture.
  • Give aphids, mealybugs, or mites a good, complete coating, making sure they are all wet! The spray is useless once dry.
  • Apply to healthy and well-watered plants. Do not spray on stressed or wilted plants.
  • Avoid spraying tender growth, blooming plants, and plants that are known to be sensitive to soap sprays – ferns, waxy leaf plants, some palms, azaleas, ivy, and some vegetables like tomatoes to avoid problems.
  • Repeat the spray application treatment in a week or so. Many pest problems require follow-up applications depending on the severity of the infestation.

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