As Smart worked in the flower bed, he began to cultivate a book idea fed by many of his passions - the centennial, which was this country's first World's Fair; the newspaper life; the rich strata of Philadelphia history.
He toyed with writing a period novel, but fiction was not so easy for a man who for 60 years has traded in hard-won fact. So he compromised and spent most of the next decade trying to evoke a real centennial-era Philadelphia through the eyes of an imagined scribe named Adonijah Hill, a widower and Civil War vet with an appreciation for detail and an eye for a wellborn journalist and early suffragist named Amanda.
The Philadelphia that 18 daily papers covered in 1876 was a metropolis in bloom. Construction had begun on City Hall, destined to become the world's tallest building. The Academy of Natural Sciences and the Pennsylvania Academy of the Fine Arts were finding new homes.
Technology drew the vast world within reach. That April, express trains would quicken the journey from Philadelphia to Boston from six days to 12 hours. Steamships would bear fresh oranges, which to a reporter from Fishtown were as exotic as diamonds.
To re-create this world, Smart spent months at Temple University's Urban Archives, where the Bulletin's morgue resides. He pored over old Harper's magazines and at the Free Library used a real estate atlas to bring alive the city's gaslit byways.
When his protagonist complains that it's not easy getting from Fishtown to the Wagner Free Institute of Science at 17th and Montgomery, know that Smart has studied the streetcar routes of the day.
The 81-year-old writer has been sharing what he knows about Philadelphia's corners since 1948, when he joined the Bulletin fresh out of Northeast High School, choosing the life of a copy boy over a one-year scholarship to the University of Pennsylvania. "I loved to write," he said, nibbling a chocolate chip cookie that his wife, Barbara Torode, had just baked and delivered to his basement library.
In 1959, he began a six-day-a-week column, "In Our Town," which he held on to for 25 years, turning out about 3,500 pieces about Philadelphia. After leaving the paper, he worked in public relations and for banks, but kept writing columns, now published by the Review, a newspaper in Roxborough.
Smart's knowledge of the city is so granular that to this day reporters at The Inquirer consult his neighborhood maps when they want to know the boundary between, say, Tioga and Swampoodle.
Smart decided to self-publish Adonijah Hill's Journal and is distributing it through Amazon.com. He went that route, he said, so no one would change his words. The book should charm rubbernecks who wander the city wondering what went on in years past.
Smart found the differences between now and then wondrous. There were no telephones, no automobiles, of course. His hero would learn of world affairs through the telegraph machine that fed his newspaper's three daily editions. The crime wave of the era involved pickpockets.
He was delighted to find some things never change - like politics. He introduces us to men of all stripes called the Mysterious Pilgrims, who meet over wine and cards at 11th and Chestnut to divvy up the day's graft.
In this, Smart, still the auger-eyed observer of human behavior, sees promise for our nation's future.
"It shows," he says, "that the parties can work together."
Contact columnist Daniel Rubin at 215-854-5917, email@example.com
or @danielrubin on Twitter. Read his blog at philly.com/blinq.