Antonio Luis thinks the idea might have come to him as he was drifting in and out of delirium while battling COVID-19 in Lankenau Medical Center.

When he left his hospital bed this spring, the 41-year-old primary-care physician, who’d become a devoted urbanite despite growing up on a small Georgia horse farm, decided to plant a community garden on what had been an eyesore on Dorrance Street in Point Breeze.

“It was so therapeutic,” Luis said. “Gardening got me outside, got me moving again after being intubated and spending 10 days in the hospital. It gives you something to look forward to. It reduces your anxiety. It lowers your stress level.”

Lots of people are picking up the trowel these days. Like the emergence of colorful wildflowers in a vast field of drab weeds, home gardening has blossomed as a wildly popular and therapeutic pastime amid the colorless anxieties of the COVID-19 pandemic.

The 21st century’s iteration of World War II’s ubiquitous Victory Gardens, these patches of vegetables, fruit, and flowers seem to be blooming everywhere — on city lots, suburban backyards, condominium patios. And whether driven by a need for a physical and emotional tonic or simply by concerns about the quality and availability of food, tens of millions of Americans are happily getting their hands dirty.

No one knows how large this bump has been, but there almost certainly are millions more home-gardeners than in 2017, when a National Gardening Association survey found that about a third of U.S. households were growing food, either at home or in community gardens.

“For a long time, society has been so focused on technology that people really weren’t looking at or appreciating nature,” said Gary Altman, a Rutgers professor who teaches in that university’s horticultural-therapy program. “The pandemic has forced a hard reset. It forced us to stop what we were doing and get out of our daily routine. A lot of people realized they’d been living stressful lives and this created an opportunity to reset.”

In the resulting rush, horticultural companies across the nation have seen their seed inventories greatly diminished or wiped out. The chairman of Bucks County’s Burpee Seeds, which has been supplying gardeners around the world for 144 years, called the demand “a tsunami.”

“We’re a seasonal business so in the spring we’re usually at the top of a bell curve,” said Burpee’s George Ball. “But this year, the length and size of that spike was something we couldn’t fathom. It went straight up, way beyond our imagination. We underestimated the reaction of non-gardeners to being suddenly pent-up indoors.”

When Penn State Extension developed a 10-week spring webinar to assist new and old home gardeners, administrators expected a few hundred enrollees. They got more than 3,000 from all over North America.

“Some wanted to produce their own food. Some were concerned about the quality and safety of food. For others, it was recreational. They just needed to get outside for their physical and mental well-being,” said Nancy Knauss, a master gardener coordinator for Penn State.

In Philadelphia, more than 2,000 signed up to participate in the Experimental Farm Network’s weekly gardening call.

“The reaction was overwhelming,” said Nathan Kleinman, the network’s co-director.

Luis’ project started as a neighborhood cleanup before he fell ill. Using social networking, he asked neighbors to meet at the lots on Dorrance, near 19th Street.

“We moved an old hot tub that had been there since 2014 and an abandoned car,” Luis said. “Then, when I got back from the hospital, we continued working there. After we cleared all the rubble, we resoiled a lot of the area and planted a bunch of crops and wildflowers.”

They planted peas, peppers, tomatoes, corn, watermelons, squash, and a variety of flowers. As the flowers have grown and blossomed, the lot has turned into a go-to spot for parents looking for a way to occupy cooped-up children.

“They just come and go,” said Luis. “Some people in the neighborhood just drop by to help. Somebody made us a raised garden bed. It’s been great. I think all the neighbors have been appreciative.”

The surge in these pandemic plots appears to be spanning demographic differences. The Penn State webinar enrollees were from cities, suburbs, and rural areas. They hailed from 34 states and a few Canadian provinces. Their interests ranged from complex soil issues to novices asking how deep to bury seeds.

“A lot of people just wanted to know where they could get seeds because so many garden centers had sold out,” Knauss said.

Ball, a past president of the American Horticultural Society, declined to provide sales data for the privately owned Burpee company.

“But trust me, we got an enormous number of new gardeners,” he said. “The uptick was a tsunami, a hurricane.”

Vegetables and salad greens were the hottest sellers, he said. New gardeners were trying out everything in Burpee’s catalog, while veterans stayed in their lane, buying in larger quantities and expanding their gardens.

According to Ball, the trend’s scope grew apparent at the end of this warm winter, when sales and orders for the seeds the company grows around the world already were brisk.

“We were spiking before COVID, but we had no idea what was in store,” he said. “I’ve been in the business for 40 years and I’ve never seen anything like it. You don’t want to experience a windfall at the expense of others, but it’s given us a different way of looking at reality.”

Gardening’s psychological benefits were apparent long before this pandemic. A 2005 study by a Rutgers psychology professor, Jeannette Haviland-Jones, determined that flowers produced both immediate and long-term impacts on happiness.

“She discovered that flowers actually were equivalent to a mild antidepressant,” Ball said. “More tangibly, the food you grow yourself has a higher nutrient level, a better taste. It’s just a deeply satisfying hobby.”

And since the mid-1990s, Rutgers has offered a certificate program in horticultural therapy. Students are trained to use plants and plant-based activities to help injured or ailing individuals and those with disabilities achieve specific goals.

“The program includes a plethora of human-science and plant-science courses,” Altman said. “The psychological benefits of gardening can be hard to measure but there’s plenty of anecdotal evidence. And there’s plenty of evidence about its physiological benefits, too. "

At some point, this pandemic will ebb and some among this bumper crop of new gardeners inevitably will drift away.

“Will we see a repeat of this spring? Of course not,” said Ball. “The game is figuring out how to guess the lasting effect. How many people will fall away after this year? But if this lingers — and we’re still seeing it — this will transform American gardening. People will continue to learn that as a hobby, gardening is way up there.”