Visiting a mushroom grower
Thick spludges of mud fall on the ground. Five men dressed in overalls are pumping the mud from a truck into a mushroom cell. The truck says “casing” on it. They’re supplying the 14 trays in the cell with compost. The trays are covered with tarpaulin. This is pulled back and an even layer of compost, covered in soil, moves along with it.
“Do you see these grains?” Peter van Asseldonk asks. He owns a large mushroom farm in Boekel. Peter picks a grain from the compost. “There is mycelium growing on it, the fungal threads that sprout the mushrooms. Come along to the next cell”, Peter says. “There you can see the next stage of growing.”
In the dark, white dots appear; there are millions of them on the top of the black casing. They don’t look like mushrooms yet. “The casing helps to keep the tray damp”, Peter explains. It’s peat from northern Russia; no other material will retain moisture like it.” He explains: “Mushrooms are a natural product. They will grow only if you copy nature meticulously.”
That’s what I do: I create autumn in a cell.
To achieve this, Peter keeps the cell nice and warm, at about 23 degrees Celsius (73 degrees Fahrenheit). Once he sees that the mycelium has grown to its full extent, the temperature goes down, to about 17 degrees Celsius (63 degrees Fahrenheit). “What I see in the mycelium? That’s a mushroom grower’s secret!” Peter smiles.
The temperature shock is a sign for the mycelium to start sprouting the mushrooms. “The same thing happens in nature. Mycelium grows well in mild autumn weather, and after an October storm, the mushrooms will start appearing.” Afterwards, Peter will keep the temperature steady at 18 degrees Celsius (64 degrees Fahrenheit). Mushrooms grow best at this temperature; they’ll grow 3 cm (1 inch) in a week; the normal size for harvesting. Peter delivers 200 thousand kilos per week; that’s 20 truckloads full.
He enters a cell that is about to be harvested. There’s not a speck of black casing visible. All trays are filled with mushrooms, like fields full of white footballs. “You can never be sure whether it works this time. Mushrooms are a natural product. I get a lot of technical help, but in the end my workmanship decides the level of success.” Content, Peter turns off the light.