U.S. retailers are experiencing mushroom shortages and climbing prices during COVID-19. Yet growers call the pandemic a “dark time” for their industry — and not just because they are growing fungi in dimly-lit mushroom houses.

Growers producing for foodservices, especially those growing specialty and gourmet mushrooms, have seen profits slashed up to 90% with restaurant closures, according to the American Mushroom Institute.

Retail sales, in contrast, have jumped. Industry leaders attribute the increase to more people cooking at home and interest in health foods. According to IRI, a data analytics firm, April retail mushroom sales were up 26% from a year ago.

But because mushroom cultivation and supply lines are complex, grocery stores are facing shortages and growers are racing to remake business models.

“The button mushrooms consumers want grow in 6- to 12-week cycles,” said Lori Harrison, spokeswoman for AMI. “You can’t just flick a switch and they’re there. It’ll take several weeks to meet demand again.”

Many U.S. growers, she said, scaled back their production after they had to donate or dump most of their mushrooms when lockdowns first started.

Now, as retail demand rises, growers are preparing to produce more mushrooms in the next cycle. But re-channeling supply lines isn’t easy.

Most producers, like Monterey Mushrooms, one of California’s leading producers, feed both retail and restaurant markets.

Following Pennsylvania, California is the No. 2 producer, accounting for 11% of mushroom production nationwide, according to National Agriculture Statistics Service.

Bruce Knobeloch, Monterey Mushrooms’ vice president of marketing and product development, said that while foodservice establishments buy 10-pound boxes, retail stores want 8- to 24-ounce packages, disrupting production lines.

“Like so many other agricultural companies, we’re scrambling to realign our production,” said Knobeloch.

Industry leaders say retail sales have also spiked because consumer polls show people are seeking foods they think will boost their immune systems.

“With this virus going on, we’ve seen bigger mushroom retail sales,” said David Law, co-founder of Gourmet Mushrooms Inc. in Sebastopol, Calif. “And our line of health products went through the roof.”

But Law’s farm produces specialty varieties primarily for foodservices, so even rising retail sales haven’t made up for restaurant losses.

About 80% of the farm’s mushrooms, Law said, go to top-end restaurants around the U.S.

There are over 2,000 varieties of edible mushrooms. According to the Mushroom Council, “whites,” or common Agaricus bisporus button mushrooms, outpace all others, representing 90% of mushrooms consumed in the U.S.

Other popular varieties include criminis and portabellas, or “browns,” and specialty mushrooms such as shiitake, oyster, wood ear and enoki.

To redirect mushrooms, Law said, his farm expanded its Community Supported Agriculture direct-to-consumer program. Before lockdown, Gourmet Mushrooms supplied CSA customers with about 450 pounds of mushrooms each week. Now, they’re supplying 4,000 pounds weekly.

Trevor Huebert, owner of Bridgetown Mushrooms, a small specialty mushroom farm in Portland, Ore., faces a similar situation.

About 90% of his business was with restaurants, he said, with remaining mushrooms sold to Whole Foods Market, farmers markets and online.

Oregon’s lockdown order, Huebert said, devastated his revenue.

“We’ve been taking orders, making deliveries to people’s homes,” he said. “We’re surviving, just scraping by. But I think long-term, these direct customers could be a new market. We’re working through this dark time, and maybe that will be the silver lining.”

Huebert said although watching revenues plummet has been upsetting, he hopes the pandemic will spark people’s curiosity about the natural world.

“It’s important that people keep curiosity about where their food comes from,” he said. “When I started studying the fungi kingdom, I became absolutely obsessed. It’s just cool to be able to walk into the mushroom house and see a cascade of mushrooms growing inside your chambers — mushrooms from all over the world, a myriad of colors inside these chambers.”