How to Sterilize Potting Soil

Sterilize potting soil before planting or transplanting your seeds or plants to ensure that they grow healthy and beautiful. The sterilization eliminates fungi, bacterial diseases and destructive bugs that may be in the soil. You can sterilize your own soil at home in your oven.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Potting Soil
• Roasting pan
• Aluminum foil
• Meat thermometer
• Oven

1. Turn your oven on to a low temperature to about 180 degrees.

2. Add peat moss, manure or compost to your soil before sterilizing it. Make sure the soil mixture is moist, but not wet. You should be able to make it into a ball with your fist and the ball should fall apart a little when you open your hand.

3. Place the soil into a metal baking pan or any container that isn't plastic. Spread the soil evenly out with your hands, making sure that it isn't deeper than four inches.

4. Cover the container very tightly with aluminum foil. Stick a meat thermometer through the foil in the middle of the container until it enters the middle of the soil.

5. Keep an eye on the thermometer by checking it occasionally until it reaches 180 degrees.

6. Keep the temperature at 180 degrees for about 30 minutes. Make sure it doesn't go over 200 degrees. Check the temperature often to see if regulating the temperature set on the oven is needed.

7. Remove the soil from the oven and allow it to cool at room temperature.

Tips & Warnings

• You can purchase pre-sterilized potting soil, which is more expensive than the do-it-yourself method and still may contain harmful fungi, disease or harmful insects that have developed in the bag during transit.
• You can also sterilize soil using a microwave by heating it--90 seconds on high per every two pounds of soil--in a closed plastic container. You have to poke a hole in the lid for ventilation and keep the temperature at 180 degrees for 20 minutes using this method.
• The soil leaves an offensive odor when being cooked. Make sure your house is well ventilated when sterilizing soil with this method.

Resources

• Great Gardening Tips

[forrie]

on 8/23/2009 Why would you place cow poop in the oven LOL Cooked cow poop. Martha Stewart would have a fit.

Couldn't we sterilize the soil, cool it, then add something like Miracle Grow after-the-fact?

[dorianbakx]

on 3/31/2009 yes, i prefeer the microwave aproach and indeed the soil leave an unplessant odor in the place... good article.