A comprehensive technical guide covering all phases of button mushroom compost preparation, from raw material selection to Phase III spawn-run completion.
Introduction to Mushroom Composting
Composting is the foundation of successful button mushroom (Agaricus bisporus) cultivation. This guide provides detailed technical information for commercial mushroom farmers.
Phase I: Outdoor Composting
Raw Materials
The standard compost recipe consists of:
Wheat Straw: 1000 kg (dry weight)
Poultry Manure: 800-1000 kg
Gypsum: 25-30 kg
Water: As needed to achieve 72-75% moisture
Process Timeline
Phase I typically takes 12-16 days:
Day 0: Pre-wet straw, build initial pile
Day 4-5: First turn, add more water if needed
Day 8-9: Second turn
Day 12-13: Third turn, add gypsum
Day 15-16: Move to Phase II tunnels
Phase II: Pasteurization and Conditioning
Pasteurization
Hold compost at 58-60°C for 6-8 hours to eliminate pests and pathogens while preserving beneficial microorganisms.
Conditioning
Gradually reduce temperature to 45-50°C over 5-7 days. This allows Actinomycetes and other beneficial organisms to convert ammonia into microbial protein.
Phase III: Spawn Run
After spawning, maintain compost at 24-26°C with high humidity (95-98% RH) for 14-16 days until mycelium has fully colonized the substrate.
Quality Indicators
Dark brown color with white mycelium specks
Pleasant, sweet smell (no ammonia)
Moisture content: 68-72%
pH: 7.0-7.5
Nitrogen content: 2.0-2.4%