DMR calls it a fast-growing mushroom: under favourable conditions the total crop cycle finishes in 4 to 5 weeks. First harvest comes 9 to 10 days after spawning, the day you mix spawn into the bed. Spawn is the grain or straw carrier that holds live mycelium; think of it as the seed, though it is not a seed.
The first flush, the first wave of mushrooms, lasts about 3 days and gives 70 to 90 percent of the whole crop. The second flush, a week or so later, adds only 10 to 30 percent. So the calendar is short and lopsided. Labour, packing and buyers must all be ready for three heavy days.