If you would like to use the dirt available in your yard instead of buying potting soil, you will need to sterilize it first. This is important so you can free the soil of any bad pests or diseases that can transfer to your plants.
Dig up the amount of soil you would like to be sterilized and place it into an oven roasting bag. Afterward, spray some water into the bag and tie it closed. Put the bag on a baking sheet and place it into the oven for 30 minutes at a temperature of 160 to 170 degrees Fahrenheit. Take the soil out of the oven after 30 minutes and poke a temperature thermometer into the bag to measure the temperature of the soil.
Pour up to 7 quarts of soil into a 7 quart plastic container to sterilize the soil using the microwave. Make sure that there is no foil on the containers. Place a lid on the container and poke a hole in the lid with a nail. This will allow the container to ventilate. Keep the temperature of the soil at 200 degrees Fahrenheit and for 20 minutes. Once the 20 minutes has passed the soil is sterilized. If you would like to use a polypropylene bag to sterilize your soil with the microwave, place the soil in the bag and put the bag in the microwave. Microwave on full power for two and a half minutes. After the time has passed, close the top of the bag and allow the soil to cool before using.
Sterilize your soil outside in sunny warm weather by using a rototiller to break up the dirt and mix it thoroughly. After you have broken up the dirt, spray the top foot of soil so that it is moist. Place a plastic tarp over the soil and put bricks around the perimeter of the tarp so it is weighed down from blowing away in windy weather. Keep the tarp on the soil for around a month and check the moistness level of the soil every two weeks. If you are placing a tarp over soil in a colder area, leave it on for two months instead. Add compost or humic acid to the soil after sterilizing the soil in the sun to restore nutrients.
Things You Will Need
- Oven roasting bag
- Meat thermometer
- Oven pan
- Clear plastic 7 quart container with lid (microwave safe)
- Polypropylene bag
- Clear plastic tarp
- Compost or humic acid