How to Grow Mushrooms from Grocery Store Purchases

Carefully cut off the base of the mushroom stem, about 1-2 cm. This is where the mycelium is most active. Avoid touching the cut part with your hands.

You can also use the cap to extract the spores, but cloning the stem is easier for beginners.
Step 2: Prepare the substrate (focus on the coffee grounds)
Coffee grounds: Remove the used coffee grounds from the percolator/machine.
IMPORTANT: Use the coffee grounds as soon as possible after use (within the same day) and make sure they are completely cool. Coffee grounds are rich in nutrients and have already been sterilized during the coffee brewing process, but can quickly become contaminated if left out.
Do not use coffee grounds that already show visible mold (green, black, pink).

Adjust the humidity: The coffee grounds should be moist but not soggy. Squeeze gently to remove excess water.

Step 1: Inoculate the culture medium
Place a layer of coffee grounds (about 2-3 cm) in the bottom of a clean jar.
Place the cut mushroom stem piece on top of the coffee grounds. You can make small cuts or scrape the base slightly to expose more of the mycelium.
Cover the mushroom piece with more coffee grounds, leaving 2-3 cm of space from the edge of the jar.
Seal the jar with the lid, but poke a few small holes (with a hot nail or sterilized needle) to allow air exchange, as the mycelium needs oxygen. If you are using a ziplock bag, leave it slightly open.
Step 1: Incubate the Mycelium

Place the container in a dark, cool, temperature-stable location (ideally between 20-24°C, such as a cupboard or pantry).
Watch for growth: Over the next few days and weeks (this can take 1-4 weeks, depending on the type of fungus and conditions), you will see a white, cottony growth spreading across the coffee grounds. This is mycelium colonization.

Warning sign: If you see any other color mold (green, blue, black, pink), it is contaminated. Unfortunately, you will have to throw this batch away and try again with greater hygiene. Step 6: Induce fruiting (temperature shock)
Once the mycelium has completely colonized the coffee grounds (the substrate will turn completely white), it is time to “shock” the mycelium to start producing mushrooms.