Share

Compost Agar Preparation

Penn State Spawn Lab Procedure for Making Compost Extract Agar

by Vija L. Wilkinson

Preparation of Peak Heated Ground Compost

  • On Spawning Day obtain 10 to 15 pounds of peak heated compost.
  • Dry by filling the bottom of a number of trays. Allow to evaporate by exposing to air or place in a drying oven. Mix every day until dry and crumbles in your hand.
  • Grind using Wiley Mill 2mm sieve. Store, under refrigeration 4°C cold room, in thick plastic bags, labeled with lot number derived from Crop number. (e.g. Crop# 1330 = Lot # 1330)
  • Obtain a copy of Compost Sample Report, from this compost. Check for compost quality before using to make media.

Compost Extract Agar

  • Mix in a 2800ml flask: 100g Dried-Ground Compost and 1500ml distilled water.
  • Sterilize for 1 hour in Autoclave, slow exhaust
  • Filter twice through triple layered cheese cloth. Add enough distilled water to the compost broth bring the volume up to 1 liter.
  • In two clean 1 L flasks mix the 500 ml of compost broth and 7.5 g Agar. Cap flask.
  • Sterilize in autoclave for 20 minutes. Cool, gently mix and pour plates.
  • Makes two flasks with 500 ml each.

What is a Compost Sample Report? See example: http://www.aasl.psu.edu/Compost%20sample%20report.pdf