All about mycelium: preservation, harvesting, and varieties to cultivate

The mycelium, the living heart of the mushroom

Mushrooms are often referred to as a vegetable, but in reality what we eat is only the visible fruit of a larger organism: the mycelium. It is the mycelium that develops in the substrate, feeds, and produces the mushrooms (also called “fruiting bodies”).

Whether you use a grow kit or want to inoculate your substrate yourself, understanding the mycelium is essential.

1. What is mycelium?

• Mycelium is a network of white filaments (hyphae), comparable to the roots of a plant.
• It develops in an organic substrate (straw, wood, coffee grounds, sawdust…).
• When conditions are right, it produces the “fruits”: the mushrooms.

2. The different forms of mycelium available

🧱 Mycelium block (already colonized substrate)

• The simplest way to start.
• Used in ready-to-use kits.
• Has a short shelf life, use quickly.

🌾 Grain mycelium (inoculum)

• Mycelium grown on grains (rye, corn, millet…).
• Allows inoculating new substrates.
• More flexible but requires more rigor and sterility.

🧫 Liquid culture mycelium (advanced)

• Reserved for experienced growers.
• Requires sterile equipment, precise conditions.

3. How to store mycelium?

❄️ Cold storage

• Fridge between 2 and 6 °C, in its original packaging.
• Lifetime: up to 3 months for a fresh block or grain.

🧊 Freezing?

• Not recommended for living mycelium: it loses its vigor.

📦 General conditions

• Keep away from light, open air, and excessive humidity.
• Avoid unnecessary handling to prevent contamination.

4. How to use mycelium?

• Prepare a clean substrate (pasteurized straw, coffee grounds, sawdust…)
• Incorporate the mycelium (grain or crumbled block), mix well.
• Place in an airtight but ventilated container → incubation for 10 to 21 days.
• Once the substrate is colonized: expose to light, moisten = triggering fruiting.

5. Which mushroom varieties to grow with mycelium?

🍄 Grey / pink / yellow oyster mushroom

• Very easy, grow on straw, cardboard, coffee grounds.

🍄 Shiitake

• Grown on logs or enriched sawdust. Takes more time.

🍄 Button mushroom

• Requires a specific substrate (composted manure), grows in full shade.

🍄 Reishi (Ganoderma lucidum)

• Medicinal plant, long cultivation on wood. For experienced enthusiasts.

👉 Discover our organic mushroom kits based on living mycelium

Conclusion

Mycelium is the true star of the fungal garden. By understanding it better, you master mushroom cultivation from A to Z. Whether you choose a ready-to-use kit or a DIY culture, it always starts with the mycelium.

🍄 Need a starting point? Discover our mycelium kits to start easily.