Potassium soap | What it is and how it is used as an insecticide

The potassium soap is one of those products that we can use for plants to stay in perfect health condition. Chemicals and minerals require much more thorough care when using pots or in our garden, when we want to end pests. If we do not go carefully, it is more than likely that we will end up killing the plant, so all our effort will have resulted in vain.

Natural remedies are very effective; In addition to having a minimum effect on the plant, they are completely respectful of nature, reducing the impact of man on the environment. They are very useful when dealing with the infinity of insects that can be presented to a plant, to scare them away or fight them once they are attacking.

One of the most effective remedies is potassium soap (also called potash ). This ecological insecticide is quite cheap. Unlike other alternatives, this acts by contact and not by indigestion, which will not affect the sap of the plant.

Taking into account all the doubts that this element raises, we have prepared this extensive article in which we are going to solve the most important ones.

What is potassium soap?

The potassium soap is a natural remedy considered by experts as one of the best natural remedies to eliminate pests. Its composition is as follows:

  • Potassium hydroxide(with formula KOH).
  • Oil(can be olive oil, sunflower oil, recycled, clean, etc).
  • Water.

This ecological insecticide is the result of a saponification process; This means that the alkali group (the potash ) will react when mixed with oil and water, resulting in a type of soap that is perfect to use as a pest prevention method, or to kill those insects. that have already been presented in them.

What is potassium soap for?

This insecticide is used so that the health of the plants is always in the best possible condition. Kill the insects that are more aggressive, such as aphids, whiteflies, mealybugs, among other pests. The potassium soap for aphid is one of the most effective remedies in the world. Some studies show that they are even more effective than fungicides, so it is worth using.

As for the price, potassium soap can cost us around € 10 for a 1L bottle. Although it is true that it is a somewhat higher cost than what other remedies would give us, you have to know that it is a very concentrated product: this means that a minimum quantity will be more than enough to achieve the result we are looking for.

To achieve the best results we will have to take care of extending the product throughout the entire plant. It will be necessary to study in detail which are the most vulnerable parts, since these will be the first ones that insects will access. These parts are the ones that should be treated properly by potassium soap .

Why should we use potassium soap?

We are increasingly aware of the impact that man has on nature and how synthetic products ( chemicals ) work. These elements can be a good solution at the moment when we are presented with a pest in a crop, to end a fungus that is destroying our plants, or in many other situations.

And although many brands sell us these products as the best option, they have many drawbacks: they are not only toxic to our health, but they could also kill the plant if we do not control the exact dose. A simple drop of a synthetic insecticide product on a wound can affect us in ways you can’t even imagine. And, of course, they are completely harmful to the environment.

With natural products, things change. It is true that we will also have to control the dose of potassium soap , but the probability of causing a disaster due to an accident will be much lower. They are not dangerous for man or for the environment, although for the pests we are trying to combat.

Therefore, more and more people are opting for natural remedies. If we do, we will be contributing to strengthen the defenses of plant beings, so, in the long run, it will not be necessary to be using similar remedies to ward off pests.

The potassium soap is an environmentally friendly insecticide very useful; It will not attack other insects that may be beneficial for plants (such as bees, which are responsible for covering certain natural processes, such as pollination). Another of its benefits is that they can be used as a subscription; At the moment it decomposes it will release a substance known as potash carbonate , with a structure designed to be easily absorbed by the roots.

They can also be stored without complications.

Potassium soap dose: How should it be used?

As we have seen, potassium soap acts by contact. This means that the moment the plague reaches the point where the soap has been placed, it will die. The cuticle of the plant is really moistened, causing the insect to die of suffocation. That is why, it is interesting to extend this product as much as possible along the most tender areas of the plant, since it will be the first access point that the insect will use to start attacking.

The correct dose of potassium soap will depend on several factors, such as the type of plant to be treated or the severity of the pest. The most normal is to dilute an amount of soap around 1-2% in water. The application system will be by spraying, getting the beam to be soaked well, as the reverse. The most advisable thing is to wait for those hours where the sun’s rays are not so intense; and it is that this soap, subjected to high temperatures, could burn the plants.

How is a product that will not leave any residue in its application, potassium soap should be applied at the time of late afternoon, and making sure that it does not rain or wind (otherwise, the product could fall from the plant, and this would reduce any effect it might have). If the plant is in a pot, once we have applied the relevant treatment we should keep it. This will make it easier for you to do the expected effect.

The treatment will work immediately, but the most common is that we have to repeat it in time. He calculates that potassium soap will have to be applied for 15 days within 3-4 months.

Benefits of using potassium acid

  • Antiplagas: Thanks to its soapy action, this product has the capacity to attack the cell membranes of the external tissues of insects. This will cause its external permeability to be lost, affecting its life cycle. The potassium soap can be used both as part of a system to prevent pests, how to combat them once they have arisen.
  • Cleaning agent:At the same time it is a cleaning agent that can be used diluted in water. It helps to clean the plants, getting that you are in the best conditions. It can be a good remedy to end dust, dirt, and many other external agents.
  • Good companion:Another of its interesting features is that it can be integrated very well with other elements to achieve the same effect. It is a remedy that facilitates moisture absorption (that is, it acts as a “wetting” agent). It can be adapted to the use of other insecticides, fertilizers or fungicides; The only thing we will have to ensure is that these elements have a pH that is above 10. Only in this way will we ensure that we do not have any kind of problem as far as compatibility is concerned.
  • Versatility: Potassium soapcan be used at any time during the plant’s growth stage, it is also valid to apply at the beginning of the transition of the flowering stage. However, in certain plants it is not recommended to apply it on the buds, but it can be done on the space surrounding the crop, as a method of prevention.
  • Good value for money:The cost of potassium soap can scare us at first, and it will not be until we make numbers when we will realize how profitable it can get us out. Taking into account that it is a concentrated product, its long duration and its effectiveness, we can conclude that its relationship between quality and price is considered as excellent.

Preparation of insecticide with homemade soap

And best of all, you don’t have to buy it, but we can also prepare homemade potassium soap on our own. There are some more or less effective methods, but we recommend the following:

Ingredients you need to prepare potassium soap

-1L of water.

-4kg of wood.

-Lemon juice.

-1L of olive oil.

-Single metal.

-1 potato

-Packaging containers.

– Metal agitator.

-Instrument to measure the pH.


  • The first thing we need is to get the wood ash. We will have to make a small fire, introduce the wood and wait for it to be completely consumed.
  • Once we have the ash, we put it in the metal pot and add the liter of water. Stir everything until a homogeneous mixture is left using the metal stirrer. This mixture should stand for about 3 days until ready to move on to the next step.
  • Let’s test if the potassium soapwe are making is on track. We will use the potato to determine if the concentration of potassium carbonate in the mixture you have prepared is valid. Introduce the potato in the mixture: if it floats, this means that the concentration is acceptable. If it does not float it is telling us that the composition is quite low. If this were so, we will have to go back to the first step and add more ash. We make the mixture again and this time we wait 48 hours to repeat the experiment again.
  • If the concentration is good, add the liter of olive oil and stir again until a homogeneous mixture is achieved.
  • The texture should be thick and thick, and this will already be considered potassium soap.
  • We need to measure the pH of the mixture, and we will do this with the tool intended for this purpose. If you have none, or do not know what we are talking about, you can go to any pharmacy to acquire it. We can buy a measuring stripto facilitate the process. In the case that the pH is between 8-9, an alkaline result is indicated , which will cause us to add 5 drops of lemon so that the values ​​are reduced.
  • We have everything ready to pack the potassium soap. It is important that the container is suitable for this, that it facilitates you to mix the proportions of water and soap every time you go to apply the product in the plant.

Some tips to keep in mind

This ecological insecticide is made with potash , being a fairly strong component. If it is not handled correctly, it could irritate the skin and mucous areas. In addition, if the resulting composition is not good, it could affect the plants.

  • Use of glove and goggles:The mixture of water and hydroxide can cause burns to the skin or eyes. Therefore, we must wear gloves and goggles throughout the process.
  • Before splashing potassium soap: If we have splashed the mixture, it is best to apply a little vinegar to calm the burning. If the splash has reached the eyes, you should run to wash them with plenty of water and go to the emergency room as soon as possible.

The danger will disappear when the water and potassium hydroxide are mixed, although this does not mean that we can relax.

How to make potassium soap to end a plague of aphids?

The aphid is one of the most common pests. There are many ecological remedies that can be applied to try to keep them at bay: for example, an infusion of garlic or nettles. Being elements that give off a very strong smell, they can be effective in certain cases. However, the most normal thing is that we need something stronger.

If we are already aware of how harmful traditional insecticides are, both for our health, and for that of our planet, then you will directly consider the option of using an ecological insecticide , such as potash soap .

A good combination of remedies to dig with this problem is to start with the two infusions mentioned, and then start with the soap. These 3 systems are perfectly compatible; According to experts, they are a practical way to end 100% with this dreaded plague.

We have already seen a way to make homemade potassium soap , which could also be worth it to end the plague. However, the way to prepare it below is rather designed to end the aphid.

Ingredients that we will need

-1 tbsp potassium soap

-1 tablespoon of 96º alcohol.

-1 tablespoon vinegar

-1L of water.

-1 spray container.

-Package, spoon, etc.

Yes, it may seem absurd to need potassium soap to make more soap, but it makes sense: We can buy Beltran potassium soap , a product that has an excellent value for money. The idea is to be able to make a large amount from a small scoop. In addition, the product that we are going to create will be much more effective, in addition to controlling the formulation at all times to avoid adding any component that can be labeled as aggressive.


  • We start by diluting 1 tablespoon of soap per liter of water. We will not be able to dissolve the mixture completely unless we use hot water.
  • We add 1 tablespoon of vinegar and another tablespoon of 96º alcohol.
  • Mix until you get a homogeneous result and let everything rest for an hour or so.
  • Place the funnel in the spray bottle and pour the product.
  • And ready, we already have potash soapready to spray.

Some considerations

-In addition to being able to use it to end a plague of aphids, it is also very practical as a solution to the red spider, cochineal, whitefly, varied mites.

-The most recommended way to use this potash soap remedy is to spray directly on the insects (in case they are seen), first thing of the day, at any time of the year.

– Although it can be used as many times as needed, it is recommended that it be done every 5 days or so. It is not that it is an especially aggressive product, but it is true that an abusive use could affect the plant in many ways.

-Fruits and vegetables can be obtained even on the same day they have undergone an application of potassium soap . Of course, it will be crucial that they have been washed in great detail, to remove any remaining product that may have remained.

Neem oil vs potassium soap

In some sources of information , neem oil is compared with potassium soap , even ensuring that they are practically the same … but it is not so.

The main difference of the oil is that it does not have a form of action by external contact. Instead, the insect will ingest it and stop feeding. The pest will stop because the insect can no longer reproduce, so the pest will be progressively diminished until it finally disappears.

The neem oil is considered a very useful complement, considered by experts as a plant (although, as the potassium soap , the origin is naturally the only problem with oil is its high wealth. Azadiractina , this element is toxic , so you have to take precautions, in addition to being very clear on what type of plant can be used and what type not.

These are the main differences between neem oil and potassium soap .

Problems using potassium soap?

The potassium soap is an environmentally friendly insecticide , this means that using plants should not cause many problems. However, how any product, poor application or poor maintenance could have chaotic results in the development of our crop.

  • Incorrect dose:Be sure to use the correct dose, which is usually one tablespoon per liter of water. The product must be well dissolved with the spoon (using hot water if necessary). If the result is not homogeneous, then you should not use it.
  • Excessive spraying:You should not wet the leaves too much, even if the pest is numerous. Keep in mind that the results will not be presented from one moment to another, but it will take some time to be visible. There will have to be a certain time frame between spraying and spraying (which, as we have seen, should be about 5 days or so).
  • Homemade Potash Soap:The benefits of homemade potash soap are more than obvious … but it’s not always the best option. If we have not followed the steps correctly, or have used inappropriate ingredients, it is very likely that we will harm the plant rather than help it. To prevent this from happening, we can always buy a commercial product already made.
by Abdullah Sam
I’m a teacher, researcher and writer. I write about study subjects to improve the learning of college and university students. I write top Quality study notes Mostly, Tech, Games, Education, And Solutions/Tips and Tricks. I am a person who helps students to acquire knowledge, competence or virtue.

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