Growing button mushrooms from a grain spawn is a rewarding and relatively straightforward process. Here are step-by-step instructions to guide you through the process:

Gather the necessary materials:

Button mushroom grain spawn: You can purchase this from a reputable supplier or obtain it from a previous successful mushroom cultivation project.

Growing medium: Button mushrooms typically grow well on a substrate composed of a mixture of organic materials like compost, straw, and gypsum.

Containers: You'll need containers or trays to hold the growing medium and spawn. Plastic mushroom-growing bags or trays work well.

Clean workspace: Ensure your working area is clean and free from contaminants to maintain the sterile environment required for mushroom cultivation.

Prepare the growing medium:

If you're using compost, make sure it is well-rotted and free from any chemical treatments.

Mix the compost with straw and gypsum in a ratio of approximately 5 parts compost, 4 parts straw, and 1 part gypsum. This mixture provides the ideal conditions for button mushroom growth.

Sterilize the growing medium:

Place the mixed growing medium in a large pot or container.

Heat the medium to a temperature of around 70-75°C (160-170°F) for about 1-2 hours. This process kills any competing organisms and pathogens that may interfere with mushroom growth.

Allow the sterilized medium to cool completely before proceeding.

Prepare the containers:

Clean the containers or trays thoroughly to ensure they are free from contaminants.

Poke small holes or cut slits in the containers to allow for air circulation during the growth process.

Distribute the grain spawn:

Once the sterilized growing medium has cooled, transfer it to the containers or trays.

Break apart the grain spawn and distribute it evenly throughout the growing medium. Aim for a spawn-to-substrate ratio of around 10-20%, depending on the specific recommendations provided with your grain spawn.

Gently mix the spawn and growing medium to ensure even distribution.

Incubation:

Place the containers in a clean and dark area with a temperature range of 21-24°C (70-75°F). The mushrooms will require a humid environment during this stage.

Cover the containers with a plastic bag or lid to maintain high humidity levels. You may need to mist the inside of the bag periodically to prevent drying out.

Mushroom formation and growth:

After about 2-3 weeks, you should start to see mycelium growth throughout the substrate. This white, web-like material is the mushroom's vegetative stage.

Once the mycelium has fully colonized the substrate (usually indicated by a solid white appearance), it's time to induce fruiting.

Lower the temperature to around 15-18°C (59-64°F) and increase air circulation by removing the plastic bag or lid.

Maintain high humidity by misting the growing area and maintaining a moist environment.

Harvesting:

Within a few days to a couple of weeks, small button mushrooms will start to emerge from the substrate.

Harvest the mushrooms by gently twisting and pulling them from the substrate when they reach the desired size (usually around 2-4 cm in diameter).

Harvest the mushrooms regularly as they mature, typically every 1-2 days.

Use a clean knife or shears to trim the mushroom stems if desired before consumption.

Remember that growing mushrooms requires attention to cleanliness and maintaining proper environmental conditions. If you encounter any issues like contamination or poor growth, consult specialized resources or seek advice from experienced mushroom cultivators to troubleshoot and improve your process.