A Psilocybe cubensis culture can colonise a jar of grain flawlessly — dense white mycelium wall to wall, no contamination, a textbook spawn run — and then stall completely the moment it is moved to fruiting. No pins for two weeks. Or it throws a flush of thin, wispy stems with tiny caps that never open. In almost every case like this the genetics were sound, the substrate was fine, and sterile technique held. What changed was the environment, and the environment was wrong for