Once the mycelium has appeared in the valleys of the casing layer it's time to trigger primordia formation.
Once the mycelium has appeared in the valleys of the casing layer it's time to trigger primordia formation. The mycelium shouldn't be allowed to colonize the casing surface since this can easily lead into an overlay. To trigger pinning, casings need three things:
the introduction of fresh air exchanges (and thus, reduction of CO2buildup), the introduction of light, and the reduction in temperature.
Ideally, the casing should be kept at 95 -100% relative humidity at this phase, and temps maintained at around 70 - 75°F / 21.1 - 23.8°C. To achieve this, remove the tinfoil/whatever from the casing completely. Place it within an appropriate moist terrarium and fan it 1-2 times a day. The ambient light of the room should be enough to initiate pinning, assuming your terrarium has some light and is somewhat see -through. At this time, if the casing layer seems dry, you *lightly* mist the casing layer with water. Not too much: otherwise fragile mycelial strands can die. The casing should remain moist but not wet.