The meadow mushroom (Agaricus campestris) is a white mushroom that pops up in grassy areas after a spring rain. It has pink gills underneath the cap where the spores are located and is a relative of the white button mushroom commonly found at supermarkets, but it has a richer mushroom flavour. Meadow mushroom seeds can be collected by taking a spore print, then making spawn and inoculating sterile straw bales in which the mycelium will grow and eventually produce the fruiting body, the mushroom. The work area and all tools must be sanitised and free of airborne spores that could contaminate the meadow mushroom spores.
Sanitise the countertop using 10 per cent bleach solution spray and wipe with a paper towel. Remove the stem from a large meadow mushroom whose gills have turned from pink to brown. Place the mushroom gill-side down on top of the white sheet of paper and cover with the glass bowl to reduce any draft that would blow the spores away. Allow to sit overnight while spores are dropping onto the paper.
Remove the glass bowl the following morning and carefully lift the mushroom from the paper using the two forks and set aside. View the spore print on the paper while holding your breath so the spores don't scatter with an exhale, and make sure it is brown.
Store spores under the glass bowl until ready to use.
Sanitise the countertop using 10 per cent bleach solution spray and wipe with a paper towel. Pour 1/4 cup of prepared agar gel medium into a petri dish, cover with the lid and place inside of the pressure cooker on top of the tuna can. Secure the lid of the pressure cooker, cook on medium heat until pressure reaches 6.8 Kilogram per square inch (psi). Cook at 15 psi for 20 minutes. Remove the pressure cooker from the heat source and allow it to cool for one hour before opening.
Ensure that the agar medium is cool to the touch. Quickly sprinkle spores onto the agar medium and replace the dish cover. Place the dish in a dark area with high humidity, such as a bathroom.
Allow spores to grow mycelium, which are white hairlike strands, for two weeks.
Sanitise the countertop using 10 per cent bleach solution spray and wipe it with a paper towel. Pour 1/2 cup of water into the pressure cooker or just enough to cover the bottom of the pot. Place a tuna can in the centre of pot. Put 2 cups of rye grain in a pyrex bowl and place it on top of the tuna can. Secure the lid of the pressure cooker, and cook on medium heat until pressure reaches 15 psi. Cook at 15 psi for 20 minutes. Remove the pressure cooker from the heat source and allow it to cool for one hour before opening.
Mix the white mycelium with the sterilised grain that has cooled to room temperature and allow the mycelium to colonise the grain until it's white and fluffy. At this point it is now referred to as spawn.
Use the newly created Agaris campestris spawn to inoculate sterilised straw bales or other growing media to produce the fruiting body of the mushrooms.
Always consult a mushroom identification book or mushroom expert when collecting meadow mushrooms. Directions for making agar solution and sterilising straw for blocks can be found on the Internet.
When mushroom identification is in doubt, do not eat the mushroom. Many are poisonous and some are deadly.