How to Grow Mushrooms on Pine Needles

Some mushrooms grow naturally in pine needles.

Mushrooms are not as easy to grow as plants. Successful cultivation depends on many factors, including sterile conditions, proper temperature and humidity, and an appropriate growing substrate. Although some species grow wild on pine needles, fresh pine needles do not provide an ideal substrate because pine oil is a natural fungicide. There are layers of needles on the forest floor, and those on the bottom, where mushrooms root, have had a chance to compost and leach their oils into the ground. You'll have to reproduce the conditions of these lower layers to use pine needles at home.

Things You'll Need

• Agar medium
• 1-quart flask
• Pressure cooker
• Thermometer
• 10 petri dishes
• Scalpel
• Live mushroom
• Electrical tape
• 10 mason jars
• Grain (wheat, rye or milo)
• Gypsum
• Sterilized gloves
• Drill
• 3/8-inch drill bit
• Stainless steel blender
• Pine needles
• Burlap bag

Instructions

1. Pour 1 ounce of agar medium, available from a mushroom-growing supplier, and 1/2 quart of water in a 1-quart flask with a tight lid. Sterilize the solution in a pressure cooker at 15 psi for 45 minutes. Let the mixture cool for 30 minutes, disinfect your hands, and pour it into 10 sterile petri dishes. Let the dishes cool for about two hours.

2. Sterilize a scalpel and then cut spores from the cap of a fresh mushroom or mycelium from the inner part of the stalk. Cut sections about the size of the tip of your finger and deposit one into each petri dish. Cover the dishes and wrap the edges with electrical tape, then store them in a sterile container at 75 to 80 degrees Fahrenheit until the spores or mycelium germinate. This can take anywhere from seven days to several weeks.

3. Check the dishes periodically and reject any cultures that are contaminated with mold. The contamination will appear as a bubble or dark area in the dish. Uncontaminated mycelium is white and fuzzy.

4. Fill 10 1-quart mason jars with 1/2 pint of grain each. You can use wheat, rye or milo, the main ingredient in bird seed. Add a cup of water and 1/3 tsp. of gypsum and mix well.

5. Sterilize the grain jars in a pressure cooker for one hour, then allow them to cool in the cooker for an hour. Remove the jars using sterilized gloves and shake each one to loosen the grain. Set them on the table to cool to 70 degrees Fahrenheit. Drill a 3/8-inch hole in the top of each jar, then cover the hole with electrical tape.

6. Fill the cup of a stainless steel blender with one quart of water, put the cup in the pressure cooker and sterilize it for 45 minutes. Let it cool to 75 degrees Fahrenheit. Choose the petri dish with the best-looking specimen and transfer the contents to the cup, put the cup in the blender and blend the contents with three short bursts lasting 1 to 2 seconds each.

7. Suck the mixture into a sterilized syringe and deposit 1/3 oz. into each grain jar through the hole in the lid. Replace the tape over each hole when you are done. Incubate the jars in a clean, dry cabinet at 75 degrees Fahrenheit until the mycelia have spread throughout the grain and are a uniform white color.

8. Prepare the pine needle growing substrate. For best results, use pine needles from the bottom of the forest floor. If you are using fresh pine needles, place them in a burlap bag and immerse the bag in water. Change the water whenever it becomes discolored by tannins, lignin and other contaminants. When the water no longer changes color, remove the needles from the bag and allow them to dry. Whether you use fresh needles or ones from the forest, pasteurize them by putting them in an oven at 135 to 140 degrees Fahrenheit for 6 hours.

9. Spread the needles in a tray, making a layer 6 to 10 inches thick. Spread the grain from the jars on top of the needles and keep the trays in an environment that is between 75 to 80 degrees Fahrenheit. Moisten the needles periodically so they are damp but not wet.

10. Pick the mushrooms when they are fully grown. Repasteurize the pine needles if you want to use them again.

Tips & Warnings

• Not all species of mushrooms will grow on pine needles. If you aren't having any luck, mix some compost or straw into the substrate.

• Successful mushroom cultivation depends on maintaining sterile conditions. Even minimal contamination will ruin your culture.

References

• Kalyx: Preparing Jars of Grain Substrate
• "The Mushroom Cultivator, A Practical Guide to Growing Mushrooms at Home"; Paul Stamets and J.S. Chilton; 1983
• Funghi Perfecti: A Simplified Overview of Mushroom Cultivation Strategies