How to Sterilize Your Houseplant's Potting Soil


Sterilizing your houseplant's potting soil before you plant can be a good idea, because potting soil not labeled "sterilized" may contain fungi or other diseases. But horticulturalists at Washington State University Cooperative Extension say these diseases are rarely present, and if they are, they pose the most threat to seedling houseplants. Since sterilizing soil gets rid of healthy soil bacteria as well, they recommend only sterilizing soil that will be used to plant seeds.

Boiling Water

Step 1

Line a colander with paper towels.

Step 2

Fill the colander with your potting soil.

Step 3

Pour boiling water over the potting soil until it is soaked.

Step 4

Leave the colander full of potting soil in the sink to drain and return to room temperature.

Step 5

Fill your planting container with the cooled, still-moist potting soil and plant.


Step 1

Place moistened potting soil in a clay pot or other oven-safe container.

Step 2

Bake the soil at around 300 degrees F until a thermometer inserted into the middle of the soil reads 140. Keep the interior of the soil at this temperature for 30 minutes.

Step 3

Remove the potting soil from the oven. Allow it to return to room temperature before using it to plant seeds.

Things You'll Need

  • Colander
  • Paper towels
  • Boiling water
  • Thermometer
  • Oven
  • Clay pot


  • Burgmansia Growers International: Starting Seeds
  • Washington State University: Houseplants
Keywords: sterilize, potting soil, house plant, sterilize potting soil

About this Author

Emma Gin is a freelance writer who specializes in green, healthy and smart living. She is currently working on developing a weight-loss website that focuses on community and re-education. Gin is also working on a collection of short stories, because she knows what they say about idle hands.