Using a Microwave to Prepare C-Fern® Powdered Medium Makes C-Fern® Even Easier to Use!
C-Fern® users who do not have access to an autoclave can successfully use a microwave to prepare Basic C-Fern® Powdered Medium.

Although the lower temperatures and shorter times of microwaving cannot guarantee sterility to the degree that autoclaving does, this method has been repeatedly used to successfully prepare contaminant-free medium.


Each packet of powdered medium contains the nutrients for 1 L of medium.

While stirring, add the contents of the packet to 1 L of deionized or distilled water. Rinse out the packet to be sure to get all the powder.

Add 10 g Difco Bacto® Agar.

Adjust the pH to 6.0 with 1.0 N NaOH.

Process the solution in a microwave unit as specified in the following table. You may need to compensate for microwave units of different powers by adjusting the suggested times. Plates should be poured ¾ full.

Be sure to use caution when heating and handling! Wear glasses, use gloves and do not leave microwave unit unattended!

For 1 L of medium prepared in a 2 L Erlenmeyer flask1
Step Microwave Time
(for 1000W output unit)
State of Solution2 Post-microwave
1 5 minutes hot remove, swirl
2 1 minute boiling remove, swirl
3 15 seconds boiling remove, swirl
4 15 seconds boiling remove, swirl
5 15 seconds boiling swirl to mix and pour Petri dishes
1Be sure to use a vessel at least twice the volume of the medium.

2The solution will boil vigorously in Steps 2-5! The medium must be visually monitored constantly so that if it starts to boil over, the power can be reduced or unit turned off briefly.

3It is important to thoroughly mix the medium by swirling the flask after each step and while pouring plates.