Depending on the raw materials this phase will last minimally 3 to even 18 days. The most important goals in this phase are:
After this phase, the compost is called “phase I-compost” or “fresh compost” (in earlier days also “green compost”).
The compost is deposited in an enclosed area. This enclosed area consists of a roster floor on which the compost lies. Conditioned air is blown through this floor. The area where the compost is deposited is called a tunnel. The first part consists of the pasteurization of the compost; this is making the compost disease-free. During the second process in this phase II the compost is conditioned, at which the ammonia in the compost is converted. After this phase, the compost is called “phase II-compost” or “spawnable compost”.
After phase II, the compost is removed from the tunnel and is mixed with ‘spawn ’. ‘Spawn ’ consists of special prepared grains of wheat that continue to grow with the mushroom mycelium. From the ‘spawn ’ the mycelium continues to grow through the compost. This process takes a minimum of 14 to 18 days. At the end of this phase the compost is called “phase III-compost” or “full-grown compost”. This phase occurs both at the tunnel companies where phase II is carried out as well, as well as at the production farm . In the Netherlands and in the more developed mushroom countries, this phase occurs at the compost company.