Save yourself some money during the growing season by taking dirt from your backyard and using it as potting soil. This process requires sterilisation through fire because the dirt may contain weed seeds, plant debris or pathogens that will interfere with healthy flower and vegetable growth. Sterilise soil that is damp but not so wet that it will not crumble if a ball of soil is crushed in your hand. Add items like peat moss, manure and compost before soil sterilisation.
Use dry wood, newspaper and matches to start a fire in a designated fire pit in a campground or yours or a friend or family member's property. Place a spit over the fire.
Place soil in a metal kettle, which you will hang on the spit over the fire. Keep the soil no more than 4 inches deep. Spray it with water to dampen the soil. Cover the kettle tightly with aluminium foil.
Place an oven thermometer through the foil into the middle of the kettle. Keep watch on the thermometer until it reaches 82.2 degrees Celsius. Let the soil cook for 30 minutes once it reaches this temperature.
Check the thermometer periodically to ensure it does not go above 93.3 degrees Celsius. Should this occur, lift the kettle off the spit and hold up over the fire so the kettle does not receive as much heat for the rest of the 30-minute period.
Remove the kettle from the spit and leave to cool with the aluminium foil in place. Use soil as desired.
Heated soil may give off an odour due to the production of plant toxins. You can also use your oven to sterilise soil as opposed to an open flame.