5 Methods Of Soil Sterilization For Vegetable Cultivation

Methods of soil sterilization for vegetable cultivation: Tomato, chilli and brinjal

Soil sterilization is a process of making soil media free from harmful microorganisms for better and quality crop production.

Also read: Important Points Soils of India

Selection of site

The site for raising nursery should be high enough, properly leveled and well drained. In low lying and poorly drained soils, the incidence of damping-off disease may be a major problem in nursery, especially during rainy season, however, soil sterilization by adopting any of the below methods may be helpful in reducing the disease incidence to some extent. Don’t select the same area which has been selected previously for raising other solanaceous crops such as brinjal or chilli.

What are the different methods of sterilization of soil?

The different methods of sterilization of soil are as follows:

  1. Solar sterilization
  2. Steam sterlization
  3. Formaline sterilization
  4. Soil fumigation
  5. Fungicide treatment

01: Solar sterilization

What is solar sterilization?

Solar sterilization is a method of sterilization soil. Sun is an ultimate source of energy (light and heat). We can use solar energy to treat soil. When we use solar heat to treat the soil, it is known as solar sterilization. It is a very cheap or no cost method.

How to treat soil beds by solar heat?

  • Open the soil with harrow or cultivator during summer month before preparation of nursery beds.
  • Cover it woth clear polythene sheet for one month.
  • Seal the sides of the polythene sheet airtight with mud.
  • This process leads to rising soil temperature during the hottest part of the day.
  • This is one of the most effective approaches for the management of disease causing soil pathogens, elimination of weeds, toxic metabolites, insect-pests etc.
  • It won’t kill the beneficial soil micro-flora.
  • This method is effective for the control of dominant soil pathogens like Fusarium sp., Meloidogyne sp., Pseudomonas sp., Verticillium dahliae, Pythium sp., and Phytophthora sp., which are responsible for many diseases in tomato.
  • Soil sterilization also increases the vigour of seedlings.

Benefits of adopting solar sterilization

  • Solar energy is free.
  • It is an organic method of soil treatment.
  • No technical knowledge: Any one can adopt this method because no technical knowledge is required.


This method is not very effective during rainy and winter season.

02: Steam sterilization

What is steam sterilization

Steam sterilization is a method of treatment of soil by using steam. It is an artificial method of soil treatment.

Soil treat method by steam

  • We need commercial boiler to generate the steam under pressure.
  • Lay out perforated pipes underground in the nursery at a depth of 20-25 cm.
  • Pass steam through these pipes continuously for 4-8 h unless the soil temperature reaches 80°C.
  • Retain this temperature for at least 30 minutes by covering the soil with polythene sheet to destroy the disease causing pathogens.
  • Soil temperature should never go beyond 90°C.
  • This process is very effective for controlling soil borne diseases, insect-pests and weed-seeds.
  • We can also use this method for the sterilization of potting medium.
  • This method is very useful to get healthy seedlings.

What are benefits of using steam in soil treatment?

  • It is an organic method of soil treatment.
  • Method is very effective.


  • This method is costly.
  • Continuos supply of electricity is necessary.

03: Formaline sterilization

What is formalin?

Formalin is a colourless solution of formaldehyde in water, used chiefly as a preservative for biological specimens”.

Soil treatment with formalin is the quickest and most efficient method to male the soil sterilozed.


  • Pulverize the soil by repeated ploughing, and drench it with 1% formalin solution up to depth of 15 cm or more.
  • Roof the nursery beds with thick polythene sheet for 5-10 days.
  • Seal the sides of the polythene sheet airtight with mud.
  • Hence, formalin fumes will enter the soil and kill all disease causing soil pathogens and insect-pests.
  • Remove the polythene sheet after a week.
  • Open the soil and leave it for few days until the formalin smell completely disappears.

Important things

  • 01: Formaline is injurious to the skin of workers since its fumes are highly toxic and irritating to human body. Handle and use it very carefully.
  • 02: The seedlings of cruciferous vegetables (cabbage, cauliflower, knolkhol) are very sensitive to formaline. Hence, don’t use formaline to treat soil if your going to grow cruciferous vegetable crops.

04: Soil fumigation

List of fumigants or formulations

  • Methyl bromide
  • Methyl iodide
  • Chloropicrin
  • Vapam


  • Methyl bromide and methyl iodide are the most common fumigants.
  • A small quantity of these chemical is enough to kill soil borne pathogens.
  • After giving treatment with these chemicals, cover the soil with thick polythene sheet for a period of 7-10 days.
  • This treatment is very effective for glasshouse and the soils of nursery beds.

Important things

  • 01: These chemicals are very poisonous. Handle it very carefully. Use protective masks. Always use gas proof cover.
  • 02: Seedlings of crops such as carnation, onion, and celery are very susceptible to these chemicals so don’t use these chemicals in the soils of the nurseries where seedlings of these crops are being raised.

05: Fungicide treatment

Also read: Soil drenching method

List of fungicides

  • Captan
  • Thiram
  • Captafol
  • Foltaf
  • Brasicol
  • Bavistin


  • The fungicide treatment is the most efficient and time saving method to manage the disease causing soil pathogens.
  • Drench the beds with 0.2% solution of any of the above mentioned fungicides.
  • Drench the beds in such a way that the chemical solution may reach a minimum soil depth of 25 cm.
  • You can also apply phorate 10G of carbofuran 3G granules @ 15-20 g per square meter at least 5 days before sowing the seeds for control of insect-pests and nematodes.

Benefits of using fungicides

  • Fungicides are easily available.
  • Availability of various fungicides in market.
  • Less hazardous to human health as compare to formalin and other chemicals.

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