Answer:
Preface
The second edition of Six Steps to Mushroom Farming recognizes that much progress in mushroom farming has taken place over the last 25 years since the original edition was published. Trends such as use of forced aeration Phase I, Phase II tunnels, Phase III bulk spawn run, casing inoculum, compost supplementation, hybrids, improved nutritional status of mushrooms, and alternative uses of post-crop mushroom compost necessitates an updated, reorganized, and expanded second edition of Six Steps to Mushroom Farming.
Mushroom farming consists of six steps, and although the divisions are somewhat arbitrary, these steps identify what is needed to form a production system. The six steps are Phase I composting, Phase II composting, spawning, casing, pinning, and cropping. These steps are described in their naturally occurring sequence, emphasizing the salient features within each step. Compost provides nutrients needed for mushrooms to grow
Explanation:
https://extension.psu.edu/six-steps-to-mushroom-farming