How to Grow Mushrooms: PF TEK The PF Tek is the method i used to grow my first mushrooms when i was a beginner in mushroom cultivation so i am happy to share the method with you all! The ratio is 2 parts Vermiculite, 1 part Water and 1 part Brown rice flour(BRF). For 6 pint jars or 12 half pint jars i use 6 cups Vermiculite, 3 cups Water, and 3 cups BRF. I mix the Vermiliculite and Water first and then add in the BRF. You can pressure cook the jars for 30 minutes at 15 psi or you can steam steri