Mycelium

Pronunciation: my-SEE-lee-um

Plural: mycelia

dna Biology & Mycology

The vegetative network of thread-like hyphae that forms the main growing body of fungi. Mycelium digests nutrients, colonizes substrates, and eventually produces mushroom fruiting bodies.

Also known as: spawn run, mycelial network, fungal roots

Etymology

From Greek 'mykes' (fungus) + 'helos' (nail), referring to the nail-like appearance of early mushroom studies

Mycelium is the foundation of all mushroom cultivation. This white, thread-like network is the actual organism - mushrooms are just its fruiting bodies, like apples on a tree.

Understanding Mycelium Structure

Mycelium consists of countless microscopic threads called hyphae. These hyphae branch and merge, creating a complex network that can span vast areas in nature. In cultivation, we harness this growth to colonize prepared substrates.

Role in Cultivation

During cultivation, mycelium:

  • Colonizes substrate by spreading through it
  • Digests nutrients using enzymes
  • Communicates through chemical signals
  • Fruits when environmental conditions trigger reproduction

Stages of Mycelial Growth

  1. Germination: Spores produce initial hyphae
  2. Expansion: Rapid growth through substrate
  3. Consolidation: Network strengthens and thickens
  4. Fruiting: Energy redirected to mushroom production

Optimal Conditions

Mycelium thrives with:

  • Temperature: 75-80°F for most species
  • Humidity: 90-95% during colonization
  • Gas exchange: Needs oxygen, produces CO2
  • Darkness: Light can trigger premature fruiting

Common Issues

  • Slow growth: Usually temperature or moisture related
  • Sectoring: Genetic differences causing uneven growth
  • Overlay: Too-dense surface growth preventing fruiting
  • Contamination: Foreign organisms competing with mycelium

Understanding mycelium behavior is key to successful cultivation. Healthy, vigorous mycelium produces the best mushroom yields.

White mycelium growing through grain substrate
Healthy mycelium showing characteristic white, thread-like growth

Where This Term Is Used