Interested in growing mushrooms at home? The PF Tek method is a simple, effective way to grow shiitake and oyster mushrooms.
The Essential Guide to Cultivating Mushrooms (Storey Publishing, 2014), by Stephen Russell, is a comprehensive guide to growing mushrooms at home, producing shiitakes, oysters, lion’s manes, maitakes and portabellas for your kitchen or for a small business. Learn how to use mushroom kits, maintain sterile procedures and a controlled environment, create grain or sawdust spawn, and use liquid cultures and fruiting chambers to produce mushrooms consistently. The following excerpt is from chapter 4, “Your First Grow.”
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If you want to grow your own mushrooms without the use of a premade kit, this is the place to start. We will focus on one basic method, by far the simplest and most efficient for amateurs learning to grow mushrooms. Originally invented by psilocybe cultivators, the PF Tek method works well for Shiitake and Oyster mushrooms, two species that are good choices for beginners.
This method, originally published in 1995 by an individual who used the pseudonym Psilocybe Fanaticus (PF), involves steaming vermiculite and brown rice flour in small, half-pint canning jars. Once cool, the concoction is injected with a syringe of spores or a liquid culture. Growers ultimately end up with colonized “cakes” of mycelium that are fruited in a small terrarium. PF was arrested in 2005 and prosecuted by the Drug Enforcement Agency for growing illegal hallucinogenic varieties, but he lives on through his legacy — this simple method for home mushroom cultivation.
There are several key reasons why this is a good method for beginners. First, it uses materials that are available everywhere. Vermiculite is available at most garden centers; brown rice flour is available at health food stores and many groceries. Second, it is possible to sterilize this substrate by simply steaming the jars in a pot on the stove. Most of the other methods described in this book require a costly pressure cooker. Third, this method uses spore or liquid culture syringes, commonly available online, as a starting point. Finally, this method only requires a fruiting chamber the size of a small plastic bin. If you’re a beginner, I encourage you not to prepare more than 24 PF jars until you’ve fruited at least one smaller round of jars successfully. Trying to overproduce before you understand all the methods only increases your chances of failure. Start with something small and manageable, and you will be rewarded.
• Half-pint wide-mouth canning jars
• Vermiculite (or sawdust, for wood-loving species)
• Brown rice flour
• Measuring cups
• Mixing bowls
• Paper towels
• Alcohol & swabs or cotton balls
• 1/8-inch (3 mm) nail
• Masking tape
• Aluminum foil
• Large pot with lid or pressure cooker
• Spore or liquid culture syringe
• Bleach solution
• 1/2 cup (8 g) vermiculite or sawdust
• 1/4 cup (60 mL) water
• 1/4 cup (45–50 g) brown rice flour
Prep: 30 minutes–1 hour
Sterilization: 1-1/2 hours
Inoculation: 20 minutes
Incubation: 2 weeks
Dunking: 24 hours
Fruiting: 2 weeks
1. Prepare the jars. Hammer four holes through each lid, using a 1/8-inch (3 mm) nail. Wipe the interior of each jar with alcohol.
2. Mix the substrate. In a large mixing bowl, combine 6 cups (96 g) of vermiculite or sawdust and 3 cups (.75 L) of water. Mix thoroughly. Add 3 cups (500–600 g) of brown rice flour to the vermiculite mixture and mix thoroughly. You should now have enough substrate to fill about 12 jars.
3. Fill the jars. Fill each jar with the vermiculite mixture to the level of the lowest ring band. Do not pack it down. Wipe the tops of the jars clean with a paper towel. Fill each jar to the top with a layer of dry vermiculite. This serves as a contamination barrier.
4. Place the lids. Place the lid and screw on the ring band. Tape over the holes using masking tape. Fold the tape over to make a small tab — this makes it easy to pull off after it is sterilized.
5. Sterilize the jars. Cover each jar with foil. I usually make 8 × 8 inch (20 cm × 20 cm) squares of foil, then press them on. To steam the jars, put 2 inches (5 cm) of water in a large pot. Add a small rack or other raised surface inside the pot to keep the jars out of the water, and place the jars on the rack. Put on the cover and steam the jars for 60–90 minutes. If using a pressure cooker, leave the jars in for 45 minutes at 15 pounds per square inch (psi). Let the jars cool in the pot. Don’t open it until you’re ready to inoculate them. Allow your jars to cool completely to room temperature before inoculation.
6. Inoculate the substrate. Move the jars into your glovebox or in front of your flow hood. Remove the foil from the jars. Put your syringes, bleach solution, paper towels, alcohol swabs, and lighter into your glovebox. Spray a piece of paper towel with the bleach solution and use it to wipe down the sides and bottom of the box, the syringes, and any other tools. Shake the syringe to distribute the spores or culture evenly within the fluid. Remove the plastic needle cover and flame sterilize the needle. If your syringe arrives disassembled, you may need to attach the needle before you can sterilize it. Sterilize by holding a flame to the needle until you can see that it is red hot. Let the needle cool, or fast-cool it by wiping it down with an alcohol swab. Pull back the tape and inject about 1/4 cc of fluid from the syringe into each hole of each jar lid. Cover the hole again after each injection. Repeat this process for all jars.
7. Incubate. Place your inoculated jars in a warm, dry, dark place for colonization, or make an incubator for this process. For most species, you’ll want the temperature of the incubation area to be in the 75–85 degree F (24–29 degree C) range. Let the jars sit and incubate for 2 weeks. You should see initial growth within your jars in 3 to 5 days, although it can take up to 7 days or more. Full colonization of the jars will usually take 2 to 3 weeks. If you see growth in any of the jars that is any color other than white, remove those jars and dispose of them immediately. Common colors are green, pink, or black. Never open contaminated jars indoors.
8. Dunking. Once your jars are fully colonized and ready to be placed in the fruiting chamber, you should dunk them in water for 24 hours before proceeding. Dunking gives the jars a burst of extra moisture before the fruiting process begins, and results in better yields. Working over a sink, simply unscrew the lid of each jar, fill the jar with water, and screw the lid on again. The colonized cake will probably float, so when you put the cap back on, you may need to force it back down into the water, causing some of the water to overflow. Store the jars in the refrigerator for this 24-hour dunking period.
9. Fruiting. Place the jars into a fruiting chamber. You may want to consider double-end casing your cakes to improve water retention for the fruiting process.
Excerpted from The Essential Guide to Cultivating Mushrooms © Stephen Russell, photography by © Stacy Newgent used with permission from Storey Publishing. Buy this book from our store: The Essential Guide to Cultivating Mushrooms.