What is Grain Spawn?
Grain spawn is a nutrient-rich starter used for growing mushrooms. It consists of sterilised grains, such as rye, millet, or brown rice, colonised by mushroom mycelium. Grain spawn is ideal for inoculating bulk substrates like straw or sawdust, allowing the mycelium to spread quickly for successful mushroom cultivation.
Preparing the Substrate
The choice of substrate depends on the mushroom species, but we commonly use:
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Straw (for oyster mushrooms) – Pasteurised in hot water (60–80°C) for 1–2 hours.
- Straw Pellets – A convenient alternative to loose straw. Rehydrate with hot water, then pasteurise by soaking at 60–80°C for 1–2 hours. Ideal for oyster mushrooms and easy to store.
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Hardwood sawdust (for lion’s mane and other wood-loving species) – Sterilised in a pressure cooker or autoclave at 15 PSI for 90–120 minutes.
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Supplemented sawdust (for higher yields) – Sterilised at high pressure to eliminate contaminants.
Mixing with Grain Spawn
Once the substrate has cooled to room temperature, we mix it with grain spawn to help the mycelium spread throughout the growing medium. We typically use 10% grain spawn by weight to promote fast colonisation and reduce the risk of contamination.
To ensure even distribution, we gently mix the grain spawn and substrate in clean containers or sterile grow bags.
Using a Laminar Flow Hood
For sterilised substrates, such as hardwood sawdust or supplemented sawdust, we carry out the mixing under a laminar flow hood. This provides sterile airflow, preventing contaminants from entering the bags or containers.
For pasteurised substrates, like straw or straw pellets, we mix them in a clean environment without a laminar flow hood.
Using mushroom grain spawn increases the success rate of mushroom cultivation and allows you to grow a variety of gourmet mushrooms at home. It is a convenient and reliable way to enjoy fresh mushrooms.
Contact Us
Have any questions or need assistance? Feel free to reach out to us for more information.