Agar plates are an essential tool in mushroom cultivation. They allow you to test spores or liquid cultures, isolate clean mycelium, and detect contamination before moving to grain. The steps below show you how to prepare reliable agar plates using Mushroom Merchant MEA Agar Premix.
Use 50 grams of MEA Agar Premix per 1 liter of distilled water.
This ratio stays the same no matter how large or small the batch is.
Add the powder directly into the water.
This prevents clumping and ensures a smooth mixture.
Heat the mixture on medium while stirring continuously.
Once it reaches a light boil, remove it from heat.
Carefully pour the hot agar into a heat-resistant media bottle.
Add a magnetic stir bar and tighten the lid about 90% to allow steam to escape during sterilization.
Place the bottle inside a pressure cooker or autoclave.
Sterilize for 15 to 20 minutes at 15 PSI.
Let the bottle cool to about 60°C.
Place it on a magnetic stir plate to keep the mixture blended.
Check the temperature with an infrared thermometer.
When the agar reaches around 50°C, it is ready to pour.
This temperature minimizes condensation inside the plates.
Move your materials into a flow hood or still air box.
Open each plate slightly and pour a thin, even layer of agar.
Avoid bubbles and reduce the amount of time plates remain open.
Agar typically solidifies in 20–30 minutes in a flow hood, and slightly longer in a SAB.
Once fully cooled, stack plates and seal them with parafilm or place them inside gallon bags.
Store the plates in a cool, dark location.
Properly sealed agar plates remain usable for 4 to 8 weeks.
For more information on pouring agar plates, visit our full guide on How to Make Agar Plates.
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