ROBERT SIEGEL, HOST:
From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.
Some foods just go with particular places. For example, Watsonville, California has cornered the strawberry market. The reason usually involves climate or soil. Mushrooms should be an exception - they grow indoors, which means they can be grown anywhere.
And that got NPR's Dan Charles wondering, why is it that half of the country's mushrooms come from one small corner of southeastern Pennsylvania?
DAN CHARLES, BYLINE: Mushroom grower Chris Alonzo is taking me on a little driving tour of the increasingly suburban countryside around the town of Kennett Square, Pennsylvania. It's an hour outside Philadelphia.
CHRIS ALONZO: That's the D'mico Farm. And up here on the right is the Bachiani Farm, which is...
CHARLES: These farms don't have fields. They have clusters of drab, windowless, cinder-block buildings all exactly the same size, each one built into the side of a hill. These are mushroom growing rooms.
ALONZO: And then up on the left here will be Kenny Davis's farm. So we have, you know, farm after farm after farm.
CHARLES: Four hundred million pounds of mushrooms every year come from farms here in Chester County, Pennsylvania. That's about half of all the mushrooms grown in the whole country. There's no real reason for this, just historical accident and some Quakers, Italians and Mexicans.
In the late 1800s, two Quaker farmers from Kennett Square, flower growers, went to Europe, where people were already farming mushrooms, and they brought back some spores. They started growing them. A few Quakers or their descendents are still in the business today.
The Italians, like Chris Alonzo's grandfather, worked on those farms and then started their own. By the 1950s there were hundreds of mushroom farmers in Chester County, mostly Italians. Like a big extended family they'd get together at the Kennett Square Inn, where I met Chris Alonzo for lunch or at Sam's Sub Shop on State Street.
ALONZO: They'd check their mushroom houses at four in the morning. And at five A.M., they'd be up there having coffee, sharing ideas.
CHARLES: 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: Fungus food.
ALONZO: I ask school groups what's your favorite food. I get: pizza, pasta, ice cream. Mushroom's favorite food is compost.
CHARLES: Chris Alonzo has taken me to a huge compost-making yard that supplies lots of farms. It's 20 acres of steaming, reeking, decomposition. There are piles of cocoa shells from the Hershey Chocolate Factory; corn cobs, chicken manure, hay and horse manure. Mushrooms are finicky. It has to be horse manure.
ALONZO: We've tried other, pig and cow, and that just does not seem to work. But with horses, it works very well.
CHARLES: There's a penetrating smell in the air, not exactly a rotting smell, more like fermenting. Tractors are rushing around like bees in a hive, turning and mixing giant steaming piles.
(SOUNDBITE OF TRACTORS)
ALONZO: Those piles are 180 degrees right now. When we see steam, we know that that's a good thing.
CHARLES: Later, they'll raise the temperature even more to kill off harmful bacteria in the compost. And every 10 weeks, fresh loads of 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 through a layer of peat moss on top.
And then, mushroom growers like Jim Angelucci, general manager of Phillips Mushroom Farms, force the fungus to deliver its fruit.
JIM ANGELUCCI: We drop the carbon dioxide level. We drop the temperature and we start to add water.
CHARLES: And the fungi apparently think it's winter; 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 - thousand of white button mushrooms. These are the mushrooms - along with their close cousins, the brown and Portobello mushrooms - that account for the vast majority of all mushrooms that Americans eat. The harvest here is underway.
ANGELUCCI: A mushroom doubles in size in 24 hours. So it's imperative that they be harvested at the proper time.
(SOUNDBITE OF MUSIC)
CHARLES: The harvest goes fast. It's done by hand. And for the past few decades, most of the workers in this room, and across the mushroom industry, have come from Mexico. This is hard work and often pays just a little more than minimum wage.
But Noelia Scharon says it's still a step up from seasonal work in the fields. She's Puerto Rican. She and her husband, who's Mexican, both used to work in the industry.
NOELIA SCHARON: My opinion, more people came here for the mushroom 'cause they didn't have to be moving around, like with the strawberries and tomatoes they had to be moving from state to state. The mushroom is all year round.
CHARLES: Thousand of workers have stayed here and they're also moving on from mushrooms. Scharon and three partners started an ice cream shop just up the street from Sam's Sub Shop.
SCHARON: Their children are going to school, learning the language, and they don't want to stay in the mushroom industry. They see how hard their parents work.
CHARLES: There's change and uncertainty on all sides of the Kennett Square mushroom industry. In fact, costs have been going up. Big farms are getting bigger and smaller ones are folding.
Chris Alonzo says it used to be really helpful having so many mushroom growers so close together; it made them all more efficient. But we're so big now, he says, we're trucking in hay for compost from a hundred miles away. There's not nearly enough housing that our workers can afford. Maybe, he says, this mushroom capital of the world has gotten too big.
Dan Charles, NPR News.