How to grow mushrooms on coffee grounds: cultivation and growing method, can spent mushroom substrate be reused?

Coffee shops today produce a fairly large amount of coffee grounds every day, so someone discovered that coffee grounds can be used to grow mushrooms, and this is a usable resource. Coffee grounds are an excellent medium for growing mushrooms (especially suitable for oyster mushrooms). Here we should thank the coffee brewing process, which has already helped sterilize the medium and is rich in various nutrients. Can spent mushroom substrate be reused? No, it cannot; it has no nutrients.

A 500-gram mushroom spawn bag is equivalent to 2.5 kilograms of fresh coffee grounds. To get this much fresh coffee grounds (left over from coffee brewed that day), the next step is that you need a container to grow mushrooms——preferably a grow bag with a filter patch, which can usually be purchased together with the mushroom spawn bag. If that is not possible, you can use a large ziplock bag, or a thoroughly cleaned milk carton, or an ice cream tub, and remember to poke four small holes around the sides.

Wash your hands thoroughly with antibacterial soap, then mix the mushroom spawn bag into the coffee grounds, breaking them up with both hands to ensure even distribution. Put the inoculated coffee grounds into a plastic bag or container, and remember to seal it.

Place the bag or container in a warm, dark environment at around 18-25°C; a fume hood or a sink will do. Leave it there for about three weeks, until it turns completely white——this is a sign that the mycelium is growing through the coffee grounds.

Once the mixture in the bag or container has turned completely white, place it in a bright spot, avoiding direct sunlight, and then cut 5x5 cm holes in the top. Spray the mixture in the container with water twice a day to prevent it from drying out——mushrooms do not grow well under dry conditions.

Over the next five to seven days, small mushrooms will emerge. Keep spraying water; they may double in size every day. When the mushroom caps have begun to turn upward somewhat, they are ready to harvest.