The box-office price for a weekday ticket to the Philadelphia Flower Show is rising dramatically this year, growing to $48 from last year’s $35 — a 37% increase.

Advance tickets have shot up to $42 from last year’s $29.95 — a 40% price hike.

Produced by the Pennsylvania Horticultural Society (PHS) and billed as the “largest indoor flower show in the world,” nearly 250,000 people attended the exhibition at the Convention Center in 2019.

“Riviera Holiday,” a riff on Mediterranean influences, is the theme at this year’s show, which runs Feb. 29 through March 8.

Organizers said the cost is reasonable when compared with the billets for a sporting event (opening-day Phillies tickets run $20 to $70) or a one-day pass to Disney World in Orlando, Fla. ($109). And the money goes to a good cause. It covers the expense of producing the show and serves as the primary fund-raiser for the nonprofit PHS.

Most people who attend the show are either PHS members or buy their tickets in advance. Nearly 35,000 attendees purchase admission at the door on the day of the show.

The show grossed more than $11 million in 2019. “And that’s not just from tickets,” said PHS president Matthew Rader. “That includes sponsorships, a share of beverage and food sales, and rentals from marketplace vendors.”

About $1.5 million of the proceeds goes to fund year-round programs supported by the Horticultural Society — community gardens, tree tenders, and expanding green space in 250 neighborhoods throughout the region.

The increased prices this year reflect consumer demand for additional elaborate displays, Rader said. He added that the show has also incurred a 3% to 4% increase in costs for utilities.

“People love the large landscaped garden exhibits, so we’ve added four new gardens, and are introducing a new garden experience at the entrance,” Rader said. “We pay for all of the garden content in the show. Those displays are not provided gratis by the exhibitors.”

The improvements are all well and good, said Richard Defeo, 76, of King of Prussia, a “longtime” showgoer. But the cost of admission this year is just too rich for his blood.

“I don’t mind if the cost goes up a bit. But I was amazed this year when I saw the price,” Defeo said.

“Last year, my wife and I paid $56.90 for two tickets that included an early purchase discount, possibly a senior discount plus a fee. With an AARP discount, the cost would be $78.60 for two,” Defeo said. “I say ‘would be’ because we will pass this year, and I’m sure a lot of others will also.”

Comparable world-class horticultural exhibits include Longwood Gardens in Kennett Square, where tickets run $25, and the much-celebrated RHS Chelsea Flower Show in London, where a day pass costs the equivalent of $90.

Rader said the rising cost of tickets has nothing to do with systemic losses at the Horticultural Society. Tax records show PHS has reported losses on its tax returns of between $1.2 million and $2 million a year for four out of five years between 2013 and 2017.

The declared value of the PHS endowment also has declined by 30% during the same period, dropping from $61.1 million to $42.9 million.

Rader said the endowment has taken a hit because “like many nonprofits, we have a lot of programs that were built on nonrecurring grants” from government entities and foundations.

When those grants expired, PHS “took the high moral ground and continued to support them,” Rader said. “Those programs have included community gardening, job training, public gardens, and landscaping in the city and at Meadowbrook Farm in Abington.”

As for the price of admission to the flower show, PHS chief marketing officer Lisa Stefano said there still are opportunities to buy less expensive advance tickets.

Adult tickets bought through the PHS website before Feb. 28 will run $43.50 (that includes a $1.50 ticketing fee); “Young Friend” tickets for ages 18 to 29 are $27.50; and tickets for children aged 5 to 17 are $18.50.

A PHS family membership, which runs $110, could save a family of two adults and two children about $14. Additional membership plans — which come with several benefits — are available through the website theflowershow.com.