Step 1: Step 1
Steam your plastic bottles for up to nine hours at 212 degrees Fahrenheit in a steam sterilizer. You will need a steam sterilizer large enough to fit the amount of bottles that you want to sterilize. Also, make sure that the sterilizer comes equipped with a temperature gauge.
Step 2: Step 2
Store your bottles over night in a room that has a germicidal light or lamp. You can purchase germicidal lights at most lighting stores or hardware stores.
Step 3: Step 3
Fill the sterilized bottles with one part white fir sawdust, one part wheat bran and one part rice bran. The exact amounts will vary depending on the size of your bottle, but you should aim to fill the bottle halfway with these ingredients.
Step 4: Step 4
Plant the mushroom seeds or mycelium in the soil mixture so that they are just covered by the soil.
Step 5: Step 5
Place the bottles in a room that is well insulated and has a relative humidity around 80%. To achieve this humidity, you may need to place a humidifier in the room with the mushrooms.
Step 6: Step 6
Wait to see the mushroom pinheads (sprouts) poking through the surface of the soil mixture. You should be able to harvest your mushrooms in an additional 10 days.