In mushroom cultivation, a "flush" refers to a distinct wave of mushroom growth. After colonizing your substrate, the mycelium will "pin" and fruit in waves.The Timeline of a FlushPins (tiny baby mushrooms) appear first. Over 5 to 7 days, they will mature, drop spores, and be ready for harvest. After the first flush is harvested, the mycelium will rest and prepare for a second, and sometimes third, flush.Maximizing YieldTo get the biggest flushes, ensure your monotub has perfect fresh air exchange (FAE) and high humidity (90%+). Dunking your substrate in cold water between flushes can also rehydrate it and trigger a new wave of growth.