Pest Problems

Soapy Water As a Spray Against Garden Pests

Killing aphids with soapy water is a largely used trick in the book of every hobby gardener. The mixture is also effective against mites, black flies and other pests. By creating a thin layer of soap around the critters, the mixture bounds and suffocates them.

Soaps are known to disrupt the cells in insects, as well, making them spill their contents. This kills the insects quite swiftly. It is also effective in getting rid of the eggs of different pests. The soap sticks on the surface and suffocates the eggs. Soapy water is also a base for other homemade sprays like the neem oil garden spray. In it, the soap acts as an agent to help dissolve the oil into water, which makes it more effective.

However, not every soap could be used to make blackfly-repellent soapy water. Soap with a lot of additives could be harmful to your plants. If you decide to make your own soapy water mixture for plants, you should go and find the purest detergent you can. Try a couple of different brands and see which one works the best! Your regular dishwashing liquid might not cut it for a pesticide.

Table of Contents:

You will find this useful if:

  • You are a hobby gardener;
  • There are blackflies on your plants;
  • There are aphids attacking your plants;
  • You are searching for a simple DIY plant spray.

Things you need to make your dish soap bug repellent

This homemade solution is probably the one with the least amount of ingredients. Surprise, surprise – all you need is soap and water.

The shortest items list:

  • Soap;
  • Water;
  • Sprayer.

All of the DIY bug spray recipes that we have written about recently have been dosed for a two-litre garden sprayer, and this should not be an exception. However, we can’t simply put exact amounts here, because it largely depends on the type of soap you are using. So, continue reading to figure it out.

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How to mix your blackfly-repellent soapy water


  1. Get your mixing container and a spoon. You can mix the solution directly in the sprayer.
  2. Fill the mixing container with water.
  3. Start adding soap one tablespoon at a time.
  4. Shake well after each spoon of soap added.

Now, this is where it gets tricky. You need to be careful about the soap you are using, it must be as pure as possible. If you can get your hands on some castile soap, it is the best option for a soapy water insecticide. If you can’t find castile soap, your next best option is some type of pure “nature lovers” detergent that has no additives like degreasers, hand balsams, artificial scents and so on.

Start by adding a single spoon of soap into your water and give it a good shake. Test spray on the plants you are willing to treat with soapy water. After a couple of days check for any damage on the plants. If there is none, you can continue testing on the pests, if you find the solution ineffective against the pest, increase the dose of soap. Remember to test spray first! You can easily kill your plants if you skip this step.

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How to apply the soapy water spray on plants

After positive results from the test sprays, you can finally treat your plants. Pump up your garden sprayer and start covering your plants with the solution. Don’t forget to go over the top and bottom of the leaves of your plants well beforehand. If there are pests on the plants, make sure you drench them well in the solution. Avoid spraying in extreme temperatures.

Treating plants like spinach, rocket and kale this way is not recommended. You will eat those leaves later on, so it is best not to cover them in soap. You will wash them, but you would need to be very thorough, as some detergents are hard to wash away. The process will eventually ruin your salad. Spraying hard fruit like apples should be fine, as they are easier to wash and they can always be peeled. But in general, avoid spraying fruits and flowers, only the leaves and stems.

Treating a couple of plants is one thing, but protecting your living area is completely different. When pests invade your property it is hard to localise the infestation and get rid of it. DIY methods could only give the invaders enough time to reproduce and set roots in your personal space.

Get in touch with a professional pest controller if you have any doubts there is an infestation in your home. The pro can at least perform an inspection. If a pest infestation is caught in its early stages it would be easier to get rid of them.

Get a professional pest inspection for your home!

Call in an exterminator to evaluate the situation in your property and help you get rid of the critter invading it.

Add a valid postcode e.g. SE1 2TH


  • Soapy water is a base for other homemade pesticides;
  • Avoid spraying spinach, rocket, kale etc.
  • Avoid spraying fruits that won’t be peeled;
  • Use the purest liquid soap you can find;
  • Always test-spray an area before treating your plants.


Have you ever treated your garden with a homemade insecticide? What was it? Did it work? Share your experience and thoughts in the comments.

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