Learn how to evaluate spawn quality before use, including visual inspection, vigor testing, and contamination detection techniques.
Why Spawn Quality Matters
Spawn quality directly impacts colonization speed, yield potential, and disease resistance. Taking time to assess spawn before use can prevent costly problems.
Visual Inspection
Healthy Spawn Characteristics
Color: Bright white mycelium throughout
Coverage: 100% colonization of grain substrate
Texture: Fluffy, cotton-like mycelium
Smell: Pleasant, mushroom-like aroma
Warning Signs
Green, black, or pink discoloration (contamination)
Wet or slimy appearance (bacterial infection)
Sour or off odors
Sparse or thin mycelium growth
Vigor Testing
Simple Plate Test
Transfer a small grain piece to agar plate
Incubate at 25°C for 5-7 days
Measure radial growth rate
Good spawn should show 8-10mm daily growth
Storage Recommendations
Store at 2-4°C immediately upon receipt
Use within 2-3 weeks of production date
Allow spawn to warm to room temperature before use
Never freeze spawn
Spawn Rate Calculations
Standard spawn rate: 7-8 kg per tonne of Phase II compost
Higher rates (9-10 kg) may be used for:
Suboptimal compost conditions
Disease pressure situations
Faster colonization requirements