how to sterilize garden soil for indoor plants?

In order for indoor plants to give us their beauty and comfort, we need to give them care. It is necessary to create conditions for them as close as possible to those in which they germinate in their natural environment: humidity, watering, light, warmth. Careful selection of soil for plants is one of the most important conditions for their growth and development. So in this article, we will focus on how to sterilize garden soil and preparing the soil for planting indoor plants and flowers.

How To Sterilize Garden Soil

How do you prepare soil for indoor plants?

Plants that are in their natural conditions and in the open field do not always need fertilizers and feeding. They have a large amount of land at their disposal, which is restored naturally.

At home, only a pot of earth is at their disposal. Such a small volume must be supplied with all the necessary substances. The earth must be moisture and air permeable, heat conductive.

Before preparing the soil for planting or transplanting a plant, be sure to read about which land is right for it.

The plant may love acidic and slightly acidic soil (for example, azalea, hydrangea, cyclamen). Orchids love soil with a high degree of air permeability, be sure to have deciduous litter in the soil, or pieces of bark and moss.

For each of the plants, you can now buy special soil in stores.

There are unpretentious plants that can be suitable for ordinary universal soil purchased in a store. Such soil, as a rule, consists of peat with the addition of useful macro and microelements.

You can prepare the soil on your own. Usually it is peat, turf, leaf, coniferous soil or humus. The prepared soil is mixed with sand, needles and other components. The harvesting process is quite long, for example, leafy soil is composted within two years. If you have your own piece of land, it will not be difficult to prepare the soil on your own.

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sterilizing of the garden for indoor plants

Before planting seedlings or transplanting flowers, it is necessary to sterilize the soil for indoor plants. The fact is that the soil may contain seeds of weeds and other plants that we do not need. But it is even worse if the ground has been infected with fungus, microbes, mold spores, or insect larvae.

To a greater extent, disinfection refers to the soil harvested on its own. Purchased soil, in most cases, is already sterile and does not need to be processed.

Time of work

If you are dealing with soil prepared with your own hands, then disinfection is carried out in advance before planting, so that all the malignant flora can be neutralized, and the useful one can recover.

Also, the soil treatment process can be carried out immediately after planting, but remember that nitrates and other harmful impurities potentially contained in the chemistry sold can harm the seed and young immature plant.

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how to sterilize garden soil?

How To Sterilize Garden Soil

There are several ways to sterilize garden soil for indoor plants, but it must be remembered that in all types of sterilizing, be it chemicals and folk remedies, the beneficial microflora of the soil also suffers.


Freezing is carried out as follows: the finished soil is taken out to the balcony in winter (preferably if the temperature is less than 15-20 degrees) and left there for 2 weeks until it freezes. Then it is brought into a warm place before thawing. This is necessary to awaken insects, larvae and plant seeds sleeping in the ground. After the heat, we again take the soil out into the cold. This can be done two or three times, at low temperatures insects and plant seeds die.

This method cannot cure all diseases (eg late blight, keel), but it is effective against insects and plant seeds.

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Calcination and sterilization

We set the oven to warm up to 80-90 degrees ( at higher temperatures, the soil will deteriorate ). At this time, put on a baking sheet foil or baking paper, pour the prepared soil onto it, spill it well with boiling water and send it to the oven for 30 minutes to ignite the soil. After the earth has cooled down a little, pour the calcined soil into the container, level it with a small layer (maximum 10 cm) and leave it to saturate with oxygen.

This method is able to disinfect the soil from all diseases and pests. The soil is enriched with oxygen and moisture.

Steaming in a water bath

The soil is poured into a colander on a double-folded gauze and placed over a saucepan of boiling water … The bottom of the colander should not come into contact with the water. The earth must be constantly stirred to warm it up evenly for an hour and a half.

This method is also able to get rid of all diseases and pests, in addition, the soil is saturated with moisture.


Soil dressing consists in the introduction of substances into it, the vapors of which are poisonous to the insects and larvae in it. This method is dangerous for humans, since the substances introduced are poisonous and maximum safety measures must be observed (carbon disulfide, cyanide compounds, chloropicrin, copper sulfate). These methods can be used outdoors on a vegetable garden or farm scale, but not on indoor plants.

how to sterilize garden soil with fungicides?

Fungicides are a type of plant pesticide. They are aimed at combating fungi and diseases caused by them. There are inorganic and organic fungicides.

Organic ones outperform the latter by the fact that they do not contain metals, they very easily dissolve in water and can treat the soil in combination with other pesticides, but organic ones are less persistent than inorganic ones.

In the use of fungicides, the main thing is to strictly follow the instructions of the drug so that they can fully demonstrate their disinfecting properties.

The method is loved by flower growers for its simplicity and speed. Fungicides can disinfect the soil from the spores of harmful fungi and diseases. You can use fungicides as a way to disinfect the soil of already growing plants.

how to sterilize garden soil with chemicals?

At home, it is necessary to use potent, chemical preparations only as a last resort, if biologically fungicides cannot cope with the disease or pest.

Chemicals come in solid, liquid and gaseous form and are applied to the soil or sprayed from above. All drugs should be used with extreme caution, some of them can even corrode the skin or cause poisoning in humans.


  • bordeaux liquid;
  • copper oxychloride;
  • oxyhome;
  • phytolavine;
  • carbonic copper;
  • formalin;
  • sulfur;
  • carbon disulfide.

High efficiency against all types of diseases and pests, kills all harmful microflora and useful, high toxicity class for humans, can harm already growing plants.

Land cultivation after disinfection

After the soil has been sterilized and disinfected by calcining or steaming, there is not only harmful but also the beneficial microflora in it, therefore, the cultivated land needs to be introduced with beneficial bacteria and microorganisms.

With the help of the fungicide, the beneficial properties of the soil can be restored. The preparation contains bacteria Bacillus subtilis, which regenerate the soil by multiplying in it, and also destroy diseases. It is necessary to spill the soil with a solution and wait for the bacteria to multiply, this takes several weeks.

On a note! Fitosporin comes in powder, liquid and paste form.

The drug must be diluted with water. The dosage is as follows:

  • to prepare the soil of indoor plants, 5 grams of powder per 10 liters of water will be enough .
  • for a paste solution, you need to take 15 drops per 1 liter of water.
  • to dilute liquid Fitosporin, 10 drops are enough for one glass of water.

Phytosporin can be used both as prevention of plant diseases and as soil restoration. In addition, it is safe for animals and humans.

Alternative natural ways to sterilize soil

There is also a way to combat diseases and pests – the introduction of many useful fertilizers, nitrogen and humus. They neutralize the action of harmful bacteria and fungi in the soil. This method refers to the moment of harvesting the soil on your own. At the same time, it eliminates harmful diseases and fungi, saturating the soil with minerals and beneficial microorganisms.

Watering with a strong solution of potassium permanganate

Spilling a pink solution of potassium permanganate is one of the easiest ways to disinfect the soil. Dissolve it in a proportion of three grams per ten liters of water. The soil is shed with this solution. Pots and boxes for seedlings are also treated with potassium permanganate.

A quick and easy way, after processing manganese becomes fertilizer, but this method is ineffective and is not able to completely sterilize the soil.

Means for normalizing soil acidity

Determinant of soil acidity or PH indicator – shows the amount of hydrogen ions in the soil. Soil acidity affects the uptake of water by the roots and the absorption of nutrients. The neutral acidity index is PH -7. The lower the index, the more acidic the soil is.

Soil classification
very acidic soilspH 3.8 – 4.0
strongly acidic soilspH 4.1 – 4.5
medium acid soilspH 4.6 – 5.0
slightly acidic soilspH 5.1 – 5.5
close to neutral soilpH 5.6 – 6.9

Most often, indoor plants like neutral or slightly acidic soil, but there are many types of flowers that love more acidic ones (azalea, hydrangea, lupine).

To determine the acidity of the soil, you can use a litmus paper and a solution of soil in water, if the paper turns red, the soil is acidic, if green, it is alkaline.

In highly acidic soil, plants lack nutrients, all beneficial bacteria stop working, the plant dies quickly. Too alkaline soil is also not very good.

Ways to increase acidity:

  • adding citric acid (0.5 tablespoons per 2.5 liters of water)
  • introduction of malic acid (10 g. per 1 liter. water)
  • introduction of oxalic acid (1 g for 2 liters of water)
  • fertilization (superphosate, peat, sulfur sulfates)

Ways to lower acidity:

You can reduce the acidity of the soil by adding chalk and special preparations and fertilizers containing calcium and magnesium (cement dust, slaked lime, ground limestone, fluff). They improve soil quality and normalize acidity. But all this does not happen immediately, lime in the soil works for several years.

Disinfection And Sterilize Of Containers For Potting Plant

Disinfection and sterilize of pot for the potting plant

All of the above methods of soil sterilization and disinfection can be ineffective when using untreated pots and seedling boxes. The disease can become on the walls and the remains of the earth. You can also process containers using drugs (potassium permanganate), rinse the infected pots with soda.

Check it out growing two plants together in one pot.

Preparations of soil for diseases and pests

Indoor plants, like open field plants, are susceptible to diseases and pests. Most often this is due to improper care on them.

Excessive or insufficient watering, excess fertilization, dry air – all this can cause diseases.

The best way to fight  is, of course, prevention. Check plants for disease by looking at leaves. Quarantine recently purchased or donated flowers until it is known for sure that it is not sick.

If the disease was discovered, you need to understand in what ways you can get rid of it.

When pests attack flowers, it is necessary to use special preparations for insecticides. These chemicals kill insects, their larvae, and eggs.

According to the spectrum of action, insecticides are divided into preparations of continuous and selective action. Insecticides of continuous action fight all insects and pests, selective – with a specific pest.

By the nature of the action, insecticides are divided depending on the action exerted on the pest:

  • contact – affect the pest at the first contact
  • intestinal – when a pest enters the body, it causes its poisoning
  • systemic – they kill all pests on the surface of the plant, inside its root system, leaves, and trunk. The poison moves through the plant itself and poisons everyone who feeds on it.

For diseases and fungi, drugs called fungicides help.

They are divided into systemic, which penetrate into plant tissues and fight the disease from the inside, and contact, located on the surface of the plant and killing the disease upon contact with them.

Fungicides can be used for dressing the soil, dressing the roots or seeds of plants, and spraying them above the ground.

The main thing to remember is that when using fungicides and insecticides, you should carefully consider the conditions of their use! Be sure to use respiratory, eye, and skin protection.

I am an avid plant enthusiast and horticulture aficionado with a deep passion for houseplants. With years of nurturing green companions, my expertise in caring for indoor foliage is well-rooted. Through my journey, I've cultivated insights into optimal plant care, propagation techniques, and creating vibrant indoor ecosystems. Join me as we explore the verdant world of houseplants together. Let's turn your living space into a thriving oasis of botanical beauty. Connect with me on and Facebook and explore more at Houseplantspro. 🌿🪴

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