Adult woman spraying plants in garden to protect from diseases

How to use insecticidal soaps

Last Updated on January 4, 2023 by Paul Guzman

How to use insecticidal soaps? Will they work? Well, they do and they don’t!  Most of our customers have tried to use some type of soap and water mixture to kill aphids and other insects.  Many tell me it kinda works, or not at all.  Eventually, most will purchase a nonorganic insecticide to make sure insects have been eliminated!

Do Insecticidal Soaps Work?

Yes, they do but there are some guidelines to follow before spraying your plants with your concoctions of soap and water.

So what is a good organic insecticide?  A good question…the insecticidal soaps found in local and big-box nurseries do work but they should be applied correctly or you will wind up damaging your plants or not removing these pests at all.

Commercial Insecticidal soaps contain potassium salts and fatty acids which are the main ingredients that kill the bad bugs.  These brand insecticide soaps are calibrated for maximum efficiency so there is less chance of damaging your plants and a better chance of killing bad bugs.

It is important to read and follow the instructions on the label of these types of products.  Safer soap products are a good alternative to harsh insecticides.

Look for the OMRI®-listed on all organic products.  OMRI stands for –  Organic Materials Research Institute.


Homemade Soaps for Insects

What type of soap should I use?   The best type of soap to use is dishwashing type soap, particularly Dawn dishwashing soap.  Typically about 2-3 tbs. per gallon of water will do the trick.

Mix it in a gallon container then pour it into your spray bottle. Save the rest for future sprayings.  Do not reuse after 6 months of storage.  It will become less effective after 6 months.

How to use insecticidal soaps

You could go stronger but this could damage the foliage of your plants. It’s important to use bottled water or soft tap water.  Hard water from the faucet contains minerals that may harm or damage plants. It also makes the foliage of plants look unsightly.

Soft-bodied insects like aphids, scales, whiteflies, psyllids, mealybugs, and spider mites are good candidates for soapy sprays.

How to use insecticidal soaps

You will have a hard time killing large type insects like caterpillars, box elder insects, and sawflies as they are too big to kill with soap.  Even the commercial type of soap will not kill them.

Do not use the following types of soaps for Insects.

  • Dishwashing machine-type soaps
  • Clothing Detergents soaps
  • Dish Soap that contains a degreaser ingredient
  • These types of soaps are harsh and will damage your plants


Will soap kill beneficial insects?

How to use insecticidal soaps
Ladybugs are beneficial insects

Another good benefit of soap insecticides is that beneficial insects such as lacewings, ladybugs, and praying mantis are not affected by soap sprays. Soapy sprays will not kill ladybugs and other beneficial insects…however, I would refrain from spraying directly at these insects.  The last thing you want is to have these beneficial bugs die or go elsewhere.

Whether you are using commercial brand soaps or your own mixture it’s important to spray directly on the bad insects and not the plant.   Again, soap insecticides work by thoroughly saturating the insects and not the plant.

Conclusion – Soapy Insecticides will work even with your own homemade mixture however, the commercial brands work best…why? Because they are calibrated and tested to work efficiently.

Got comments or questions? Please comment below.

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