Why a Small Pennsylvania Town Is the Mushroom Capital of the WorldS

To grow mushrooms is to let things rot, so something's a lot of things are rotten in the state of Pennsylvania.

The Atlantic's deep dive into the dark side of truffles last week got us wondering about their more prosaic cousins: the portobellos and white buttons you find shrink-wrapped at the supermarket. We've also seen DIY mushroom growing kits sprouting in foodie kitchens, but what does industrial mushroom production look like? Those musings lead us, unexpectedly, to Kennett Square, Pennsylvania—a small town in the state's southeastern corner and the Mushroom Capital of the World.

Half of America's mushrooms come from the area around Kennett Square, which is intensely proud of its mushroom heritage. The town closes its streets every year for a two-day mushroom festival. This past New Year's Eve, they dropped an 800-pound mushroom in lieu of a ball.

What's curious about the whole mushroom thing in Pennsylvania is that it's all a historical accident. There's nothing in the Pennsylvania soil that is better suited for mushrooms (which are grown indoors, anyway). But, nearly 150 years ago, according to local legend, a couple of Quakers decided to grow mushrooms in the otherwise wasted space under the elevated beds in greenhouses. As word spread, more and more farmers came to try their hands at a fungal fortune.

Why a Small Pennsylvania Town Is the Mushroom Capital of the WorldS

Crates of portobello mushrooms from Kennett Square. AP Photo/Dean Fosdick

Kennett Square did have one geographic advantage, although not a particularly unique one. Being close to a large city in the early 20th century meant an ample supply of horse manure, which is still an ingredient for growing mushrooms today.

How to farm mushrooms

Just outside of the town lie 20 acres of steaming compost, made up of horse manure, hay, and—this being Pennsylvania—cocoa shells from the Hershey chocolate factory. This is how you make mushroom food.

The compost is pasteurized and then inoculated with mushroom spores. For days, the fungus grows as a spidery white web. Then, changing the temperature, water, and carbon levels prompts fungi to reproduce. Mushrooms, after all, are the fruiting body—in other words, the sexual organs—or fungi. Right before harvest, certain mushrooms can double in size in just one day. All of this growing takes place in windowless, temperature-controlled buildings that line the roads along Kennett Square.

Why a Small Pennsylvania Town Is the Mushroom Capital of the WorldS

Inside a mushroom farm. Mohd Hasmi Hamidi/Shutterstock

What about underground?

If you're ticking off the characteristics of the mushroom's favored climate—damp, cool, dark—you might start to wonder about underground caves. What if we could leave the climate control to nature?

Until 2010, Creekside Mushrooms—just up the state, past Pittsburgh–grew mushrooms in 150 miles of abandoned limestone caves. It was, according to the company, the only underground mushroom farm in the U.S. and the largest mushroom facility in the world. But, with ordinary button mushrooms—not to mention the costs of climate control—so cheap, the underground mushroom farm went out of business three years ago. Its owner told the food magazine Spezzatino that warmer climates and rising energy prices could possibly one day force mushrooms back underground.

It really is bizarre, if you think about it, that America's mushroom output is concentrated in a small corner of Pennsylvania. That these mushrooms all grow in windowless, climate-controlled buildings seems to epitomize modern agriculture, where technology has increasingly divorced the crop from local land. But the natural and unnatural aren't necessarily at complete odds.

In a one-kilometer abandoned railway tunnel in Australia grow shitake, oyster, shimeji, and other exotic mushrooms—none of them native to the continent. The dark, damp interiors of Li-Sun Exotic Mushroom Farm are an unnatural but accurate approximation of the mushrooms' native habitats.

Why a Small Pennsylvania Town Is the Mushroom Capital of the WorldS

Why a Small Pennsylvania Town Is the Mushroom Capital of the World

Why a Small Pennsylvania Town Is the Mushroom Capital of the WorldS

Photos by Nicola Twilley

Abandoned tunnel mushroom farming has yet to catch on, but we can still idly speculate about its potential. Cities are full of old tunnels, aqueducts, and subway stations fallen into disuse. What if abandoned infrastructure could be repurposed for urban fungiculture?

Instead of dabbling in DIY mushroom-growing kits, city dwellers could cultivate their own subterranean plot and make Myrtle Ave mushroom risotto. [NPR]

Lead image: subin pomsom/Shutterstock