The Petri Dish is used to contain the nutrient mixture (MEA or PDA) when making a Nutrient Plate.

A Nutrient Plate is a Petri Dish with a ready-made nutrient mixture (see recipe below) on which a mycelium culture can be grown. Petri Dishes are sold in a sterilised, sealed plastic pack of 10.

MEA Ingredients:

11g Agar Agar Powder
7-10g Barley Malt Extract
500ml boiling water

PDA Ingredients:

11g Agar Agar Powder
1-3g Dextrose Powder
500ml hot potato broth

Method:

Mix all the ingredients very well and until there are no lumps.
Pour mixture into a Glass Beaker and cover with Heavy Duty Foil and wrap tight (the foil is a splash cover).
Place the Glass Beaker in a Pressure Cooker and get it to operating temperature and pressure.
From this point, cook for 45 minutes.
Remove Glass Beaker from the Pressure Cooker and wait for the temperature of the mixture to drop to 46°C.
Pour into the Petri Dishes
Allow the mixture to cool, then seal with Parafilm
This recipe makes 40x65mm plates