Farms in Chester County, Pa., produce 400 million pounds of mushrooms annually. That's about half of all mushrooms grown in the U.S. They're grown indoors in long, gray cinder-block houses built into the side of a hill.
Every 10 weeks, the beds inside the mushroom rooms are filled with compost mixed with spores, and covered with peat moss. The spores germinate and create a thick web of white threads called mycelia, shown here. As the fungi try to reproduce, they send up their fruit — the mushrooms.
Shiitake mushrooms in a growing room at Phillips Mushroom Farms, one of the big mushroom producers in Kennett Square.
A Mexican worker at Phillips Mushroom Farms. Workers are paid a little more than minimum wage to cut at least 55 pounds of mushrooms an hour.
Southeast Asian workers cut shiitake mushrooms at Phillips Mushroom Farms. The mushroom industry in Chester County, Pa., has relied on several waves of immigrant workers, beginning with Italians in the late 1800s.
At an industrial compost facility that supplies the mushroom industry in Kennett Square, ground-up corn cobs are mixed with chicken manure, hay, cocoa shells and horse manure. Over time, growers have learned that mushrooms grow best with this blend of nutrients.
Cocoa shells from a Hershey's chocolate plant in Hershey, Pa., are just one ingredient in the compost that mushroom growers use to feed the fungi.
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Here's an astonishing fact: Half of America's mushrooms are grown in one tiny corner of southeastern Pennsylvania, near the town of Kennett Square.
But why? It's not as though this place has some special advantage of climate or soil, the kind of thing that led to strawberry fields in Watsonville, Calif., or peach orchards in Georgia. Mushrooms can grow indoors. They could come from anywhere.
No, what turned Kennett Square into the Mushroom Capital of the World was nothing more than historical accident, combined with the presence of some very industrious Quakers, Italians and Mexicans.
The story starts with the Quakers.
Sometime around 1885, according to local lore, two Quaker flower growers from Kennett Square were bothered by wasted space under the carnation beds in their greenhouses, and they thought of growing mushrooms there. So they steamed off to Europe, where people were already farming mushrooms, and brought back some spores.
They were Kennett Square's original mushroom farmers. A few Quakers — or their descendants — are still in the business today.
They hired some Italians — laid-off workers from nearby stone quarries — to handle some of the hard physical labor. And then the Italians started their own farms. So did their sons and cousins. By the 1950s, there were hundreds of mushroom farmers in Chester County, and most were Italians.
Many are still there (although there are fewer, but we'll get to that).
Chris Alonzo, president of Pietro Industries, one of the bigger mushroom companies, takes me on a little driving tour of the area. As we go, he points to the mushroom-growing rooms: clusters of drab, windowless, cinder-block buildings, all exactly the same size, each one built into the side of a hill. "There's the D'Amico farm," he says. "And up here on the right is the Basciani farm. And on the left here is Kenny Davis' farm. So we have farm after farm after farm."
Like a big extended family, the mushroom farmers — including Alonzo's father and grandfather — would get together at the Kennett Square Inn or Sam's Sub Shop on State Street. "They'd check their mushroom houses at 4 in the morning, and at 5 they'd be up there having coffee, sharing ideas," says Alonzo.
That's part of the secret to this clan's success. They had to learn from each other, because there was almost nobody else doing this. Fungus farming is completely different from growing plants, like wheat or potatoes. There's something weird and magical about it.
It starts with the most basic thing: the compost that feeds the fungi.
It Takes A Lot Of Manure
Chris Alonzo takes me to a huge compost-making yard that supplies lots of nearby farms. It's 20 acres of steaming, reeking decomposition. There are mounds of cocoa shells from the Hershey chocolate factory, corn cobs, chicken manure, hay, horse manure.
Mushrooms are finicky. They don't like just any kind of manure. "We've tried others, pig and cow [manure], and that just does not seem to work," says Alonzo. "But with horses, it works very well."
Loads of this compost will refill long beds inside those climate-controlled cinder-block buildings across Chester County. Spores will get mixed in.
The spores will germinate, and silently, in the darkness, a thick web of white threads — mycelia — will spread through the compost and a layer of peat moss on top.
Finally, mushroom growers force the fungus to deliver its fruit. "We drop the carbon dioxide level, we drop the temperature, we start to add water," says Jim Angelucci, general manager of Phillips Mushroom Farms.
This apparently convinces the fungi that winter is coming. They panic and try to reproduce. They send up mushrooms, which in nature, would release spores.
Angelucci shows me the result, and it's spectacular. The beds are covered with a mass of pure white, like bubbling foam: thousands of white button mushrooms. These are the mushrooms — along with other strains of this same species, the brown and portobello mushrooms — that account for the vast majority of all mushrooms that Americans eat.
In this growing room, the harvest is under way. Angelucci says it has to happen quickly. "A mushroom doubles in size every 24 hours, so it's imperative that they be harvested at the proper time."
This is hand labor. For the past few decades, most of the workers in this growing room, and across the industry, have come from Mexico.
It's hard work, and many workers earn only a little more than minimum wage.
Putting Down Roots For Steady, Hard Work
But, says Noelia Scharon, it's still a step up from seasonal work in the fields. She's Puerto Rican and grew up in Chester County; she and her husband, who is Mexican, both used to work in the mushroom industry. "My opinion — more people came here for the mushrooms because they didn't have to be moving around. With strawberries and tomatoes, they had to be moving from state to state," she says. "The mushroom [harvest] is all year round."
Thousands of mushroom workers have remained in the area, even after they moved on from mushroom jobs. Scharon and three partners started an ice cream shop just up the street from Sam's Sub Shop.
"Their children are going to school, learning the language. They don't want to stay in the mushroom industry; they see how hard their parents worked," Scharon says.
There's change and uncertainty, in fact, on all sides of the Kennett Square mushroom industry.
Costs have been going up. Big farms are getting bigger, and smaller ones are folding. Only 60 farms survive in Chester County, but production continues to increase.
Chris Alonzo says it used to be really helpful to have so many mushroom growers so close together. It made them all more efficient.
But they're now so big, he says, that they're trucking in hay and horse bedding — for compost production — from farms and stables a hundred miles away. There's not nearly enough affordable housing for all the workers. It's making mushroom farming here more expensive. Maybe, he says, this mushroom capital of the world has actually become too big.