How to Sterilize Bark for Orchids

Most houseplant orchid varieties thrive in soilless potting mixes that primarily contain bark, including the phaleanopsis and other epiphytic varieties. The bark provides a coarse, sterile medium for the plants to anchor their roots. The orchids only require minimal nutrients from the growing medium, since they receive most of their growing needs from moisture and air. Reusing the bark for repotting or growing new plants can spread plant diseases and pests unless it's properly sterilized first.

Disposable aluminum pan
Foil
Oven thermometer

Instructions

- 1
  Preheat the oven to 200 degrees Fahrenheit. Move the oven rack to the second lowest position.
- 2
  Spread a 2-inch layer of used bark in a disposable aluminum roasting pan. Mist the bark with water until it's evenly moistened throughout.
- 3
  Cover the pan with a sheet of aluminum foil. Insert an oven thermometer through the foil in the center of the pan, burying the thermometer probe in the bark.
- 4
  Bake the bark for 30 minutes, or until the thermometer reads at least 180 F. Remove the pan from the oven and allow the bark to cool to room temperature.
- 5
  Use the bark immediately or leave it covered in the pan until you are ready to use it. The foil cover keeps the bark sterile.

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