Whilst insecticides are effective for killing aphids, they are awfully bad for the environment. Many gardeners want more natural ways to kill and remove aphids from their plants. Could soapy water be one of these methods?
The Quick Answer
Can You Kill Aphids with Soapy Water?
You can kill aphids with soapy water but you will need to use strong, chemical soaps. This is not advised as it can kill both aphids AND your plants. Instead, try a natural soap that will remove aphids from your plants but may not kill them.
Does Soapy Water Kill Aphids?
The simple answer to this question is, it depends.
There are soaps with insecticidal properties that will kill aphids both quickly and effectively. However, it will also kill pollinators and insects that are helpful to your gardens so you should avoid these if you can.
More natural and kinder soaps are less likely to kill the aphids living on your plants. But you can still use soapy water to help you rid your garden and plants of the little pests.
As well as this, using soaps with high amounts of vegetable oils can often smother the aphids, killing most of them, without harming larger and more helpful insects.
Does Water Kill Aphids?
Water does not kill aphids, in essence, all animals need some form of water. But you can use it to get rid of aphids.
Aphids as a whole are tiny and can easily be knocked off your plant by a jet of water from a hosepipe. In fact, they’re so small, you don’t even need that much power. Spraying them directly with a spray bottle will provide you with enough force to knock them from your plant.
Whilst this is a good method, it would have to be repeated as simple water does not deter the aphids from coming back.
Do Aphids Like Soapy Water?
There is no point in trying to use something that aphids like to get rid of them. Thankfully, they do not like soapy water at all.
Applying a spray or small amount of water and dish soap to the afflicted plant will drive the aphids away. However, you will need to reapply this solution every few days. This is because the effect will become more and more dilute and new aphids will be happy to reoccupy the plant as they cannot be harmed by the left-over solution.
What Soap Solution Should Be Used?
As mentioned earlier, soaps with insecticides in them should be avoided as they will kill helpful pollinators, such as bees, as well as the aphid pests. Using a standard dish soap solution is the best way to rid your plant of aphids without harming the environment.
When making your soap solution make sure to not use detergent. Detergent does a lot more harm than good in your garden and using pure and natural soap will do the job just fine without any negative side effects.
In fact, natural soap contains more plant and vegetable oils than detergent and these ingredients are what helps to smother the aphids.
The best way to apply the soap solution is via a spray bottle. In the bottle, mix 1 litre of water to 5 tbsp of dish soap. Make sure to give it a good shake before applying to your plants. It is always a good idea to test your spray solution on a singular leaf before applying it to the whole plant. Spritz a little on one of the leaves and wait for a few hours.
By this point, you will be able to see if there has been any effect on the aphids on that plant and you will also know if your plant has been damaged by the soap solution.
Will Soapy Water Kill Plants?
If you make your soap solution using natural and un-fragranced soap, it should not cause any damage to your plants. However, you should still check any solution that you make up.
Using perfumed and stronger soap solution will cause damage to your plants. Many non-natural detergents contain very strong chemicals that will cause serious harm to your plant.
Natural soaps should not contain any chemicals that could damage your plants. But make sure to read the ingredients on whatever soap you use.
Some soaps will claim they have natural properties but in one way or another still have some of the harmful ingredients that you need to avoid.
To summarise, harsh chemical soaps can kill aphids but damage your garden. Natural soapy water will kill some aphids but not all, and it will remove the rest.
Soapy water should be sprayed on your plant every few days to prevent aphid growth. Check the ingredients of the soap you use and test your solution on a singular leaf before applying it to the full plant.
Ryan is a keen gardener from the UK who’s spent years dealing with countless, common pests over the years so knows the ins and outs of how to deal with pests in the garden