How to Make Grain Spawn
Grain spawn for growing mushrooms
Making grain spawn is an important step for growing mycelium. Sterilized grain such as rye, wheat, oats, birdseed or millet is inoculated with spores or mycelium. The mycelium grows throughout the grain, creating a dense mass of fungal tissue that can be used to inoculate a substrate. Common substrates include sawdust, wood chips, coco coir and straw.
Here are the general steps for making grain spawn:
- Start by sterilizing your chosen grain in a pressure cooker or autoclave. The goal is to kill any potential contaminants and create a sterile environment for the mushroom mycelium to grow. See below for complete instructions.
- Once the grain has been sterilized, allow it to cool to room temperature.
- Inoculate the cooled grain with the grain spawn, liquid culture or spores. Work in a sterile environment or by using a syringe to inject the spores or liquid culture into the grain. Work in front of a flow hood or in an airless chamber if possible.
- Allow the grain to incubate in a warm, dark place until the mycelium has fully colonized the grain. This can take anywhere from a few days to a few weeks, depending on the species of mushroom and the conditions of your incubation setup.
- Once the mycelium has fully colonized the grain, it is ready to be used to inoculate your substrate. This can be done by mixing the grain spawn with your chosen substrate and allowing it to incubate until the mushrooms begin to fruit.
Mycelium colonizing in grain
Mycelium is the vegetative part of a fungus that is made up of a network of thread-like structures called hyphae. When you inoculate grain with mushroom spores or mycelium, the mycelium will begin to grow and colonize the grain. It breaks down the nutrients in the grain while spreading throughout it. Here are some things to keep in mind when your mycelium is colonizing in grain:
- Temperature: Mycelium grows best in a warm, humid environment. For most mushroom species, a temperature range of 70-80°F (21-27°C) is ideal. Make sure to monitor the temperature of your incubation setup to ensure that it stays within this range.
- Moisture: Mycelium needs moisture to grow, but too much moisture can lead to contamination. The ideal moisture content for grain spawn is around 40-60%.
- Contamination: Grain spawn is particularly susceptible to contamination, so it’s important to maintain a sterile environment during the inoculation and colonization process. Use proper sterilization techniques. Also, work in a clean, well-ventilated area to minimize the risk of contamination.
- Colonization time: The time it takes for mycelium to fully colonize grain can vary depending on the species of mushroom and the conditions of your incubation setup. In general, it can take anywhere from a few days to a few weeks. Check your grain spawn regularly to monitor its progress.
- Harvesting: Once the mycelium has fully colonized the grain, it is ready to be used to inoculate your substrate. You can either use it immediately or store it in a sealed container in the refrigerator for a few months. When you’re ready to use it, simply mix it with your chosen substrate. Colonize, then providing fruiting conditions.
Overall, growing mushrooms can be a rewarding and fun experience. It requires careful attention to detail and a sterile environment.
Sterilizing grain
Sterilizing grain is a crucial step in the process of making grain spawn for growing mushrooms. The goal is to kill any potential contaminants and create a sterile environment for the mushroom mycelium to grow. Here are the general steps for sterilizing grain:
- Start by selecting your grain. Rye, wheat, oats, birdseed and millet are common choices for grain spawn.
- Rinse the grain, then soak overnight in water
- Strain the grain. Cook grain in fresh water in a large pot by bringing to a boil, the simmering gently for 20 minutes.
- Strain the grain, then spread out on baking sheets or screens. Allow it to dry slightly for about an hour.
- Place the grain in jars or autoclavable bags. Make sure jar lids are loose and cover with foil to prevent water from getting inside. Fold bags over with the open end folded under the bag.
- Place the jars into a pressure cooker or autoclave.
- Bring pressure to 15 psi, then reduce heat and maintain 15 psi for 90 minutes,
- Release pressure.
- Remove bags only after pressure has been completely released.
- Spread bags out to cool or allow them to cool inside the pressure cooker overnight.
It’s important to note that sterilization is a critical step in the process of making grain spawn. Any failure to sterilize the grain properly can result in contamination and failure of the entire project. It’s also important to work in a clean, well-ventilated area. Use proper sterilization techniques to minimize the risk of contamination.