How to Sterilize Potting Soil: 8 Gardener-Approved Methods
To sterilize your soil, place foil on a baking tray and top with a layer of garden soil. Then put it in the oven for 20–30 minutes at maximum temperature.
At freezing temperatures, most microorganisms die, but harmful bacteria can still survive. That is why it is best to freeze the soil twice.
Put some soil in a bag, poke a few holes on the top with a fork and microwave on maximum power for 10–15 minutes.
Use Hydrogen Peroxide
Prepare a 3% mixture of hydrogen peroxide by adding 30 ml of hydrogen peroxide per 1 liter of water.