Very few buildings have a fourth floor. It is a height reserved for apartment blocks, hotels, or fancy offices. In a repurposed building in the south of The Hague, however, the fourth to the eight floors belong to a farm.

Sweep the straw and soil from the floors of your imagination. The New Farm in the Groente-en-Fruitmarkt district refers to itself as a “hub for smart urban food solutions and awareness.” Plucked out of context, “urban food” sounds like something on the menu of a seagull, but The New Farm’s crowning glory is a humungous greenhouse—the largest rooftop farm in Europe. When I peeked on the UrbanFarmers site, all of its “high power cucumbers,” “tatami tomatoes,” and “big city swimmer filets” were all sold out.

Somewhere beneath this high-tech, green, internship-friendly Farm is Haagse Zwam.

“I grow mushrooms in waste coffee grounds,” says entrepreneur Annelies Goedbloed. A sprightly, fascinated lady, she quit a successful job as the manager of an IT company to go circular.

“I was fed up with it,” she says. “I was thinking really want to do more. I went to a talk by Gunter Pauli, the founder of The Blue Economy, and he really touched me. I just cried and cried. I began trying to recycle the metals out of these devices we were using—as a manager, I saw so much hardware going to waste.”

“I did not succeed. My family said: “You have to stop.” But I’m not someone to give up easy.”

And so, logically, she did stop. To start a mushroom farm.

“Mushrooms are leaders of nature,” she continues. “They break down everything into smaller elements that can be eaten by roots of plants and trees. The remains of my growing medium are very good compost; I’m closed-loop. This is vertical farming.”

For most of us, coffee is an ephemeral buzz, but the long journey from the tropics to the coffee roasters to the shops doesn’t end with its heavenly bitterness upon our tongues. The sacred bean is thrown into the bin along with everything else: the tissues, the hair, the gum.

As it turns out, once sterilised by boiling water, coffee grounds are the perfect medium in which to grow mushrooms. They are in abundant supply. In fact, the cafes in Annelies’ network pay her to collect their used grounds.

“I collect 100 kilos of coffee waste per day,” she says. “They phone me, and I have to say ‘I’ll only collect when you have at least 10 kilos’. We have about 50,000 kilos of coffee grounds here right now.”

Leading us into her “dark room,” the enterprise begins to look more like a top-secret alien incubation project. But according to Annelies, if she does a good job, she can convert 20% of that original weight into premium mushroom here. And not just any mushroom, but oyster mushroom—“the beef steak of the mushrooms.”

Customers are snapping them up. She can’t say exactly whom she sells to (though lets slip de Boterwaag and Hagedis), so this might require some deft investigation when oyster mushrooms are on the menu

That is, if you don’t see Annelies zooming down the streets on one of her electric bicycles.

And if you do happen to see her, then observe her attire. Take note of her shoes. Witness the look of professional, passionate, determination in her eyes. Don’t look at the coffee grounds—they’re not the important bit of this story. Because Annelies is the face of modern farming, hunting for the ugly, the unloved, the forgotten, and gently working it all back into earth.