It is nearing the end of September and the amateur green thumb is at a crossroad. What should I plant in the garden? Can I plant anything this late in the year? Is it time to seed the lawn? What about my shrubs?

These are the kinds of questions Don Hastings Jr., a third-generation horticulturalist, loved to answer during his call-in radio show. He never claimed to have all of the answers, but he wanted to get to know the caller and help if he could, said Chris Hastings, the younger of his two sons and a fourth-generation horticulturalist.

“He enjoyed the people every bit as much as the plants,” Hastings said, of his father. “A lot of his gardening career was a very personal experience between him and other people.”

Donald Madison Hastings Jr., of Roswell, died Sept. 18 at his residence in his sleep. He was 84.

A memorial service is planned for 10:30 a.m. Thursday at All Saints’ Episcopal Church, Atlanta. Cremation Society of Georgia was in charge of arrangements.

Don Hastings was born into a legacy of horticulture. His family’s expertise dates back to 1889, when Hastings’ grandfather, Harry George Hastings started H. G. Hastings and Company, a mail-order business based in Interlachen, Fla. The company, which moved to Atlanta in the early 1900s, sold seeds, which was how gardens got started in those days, Chris Hastings said. Donald Hastings Sr., succeeded his father as chairman of the seed company, which eventually opened a chain of nurseries across metro Atlanta. Don Hastings was president, to his father’s role as chairman, when the family sold the company in 1976. Though there is still a nursery business in the Atlanta area that bears the Hastings name, it is not associated with the family, Chris Hastings said.

“My father, like his father and grandfather, was a seedsman,” the younger Hastings said. “He grew up in an era prior to retail nurseries. Back then people would give each other seeds and buy seeds, so I think he had a love of growing things from seeds.”

Don Hastings, born in Atlanta, graduated from Decatur Boys High School and went on to Cornell University, where he earned a degree in horticulture in 1950.The Army Reservist returned to Atlanta after college and immersed himself in the family business.

“He was sort of the voice of southern gardening after our father died,” said his sister, Mary Louise Hastings Clarke.

Don Hastings loved to talk gardening with anybody, said Staci Catron, the director of the Atlanta History Center’s Cherokee Garden Library.

“He could talk about southern gardening, how to do it well, and he could do that for lay people,” she said. “You didn’t have to be an expert to follow him, and he would talk to anybody. It didn’t matter how much you knew about gardening.”

After the family sold their company, Hastings spent a considerable amount of time traveling the globe, trying to solve seasonal vegetable supply problems. He spent two years in Egypt and he lived in Malaysia, the Philippine Islands, all the time lending his “agricultural expertise,” his son said.

In 2005 the Southeastern Flower Show presented Hastings with is highest honor, the Robert McGee Balentine Trophy. At the time, Hastings told The Atlanta Journal-Constitution that gardening, like parenting, was all in the way plants were nurtured. He talked about that thought in his biography entitled “Rich Harvest,” one of six books he authored.

“Gardening is not a study but an experience,” the book says. “Because of unpleasant childhood experiences with them, I have no desire to plant junipers, so I don’t. But I love camellias. Guess what? They do fabulously for me.”

In addition to his son and sister, Hastings is survived by his eldest son, Dr. Don Hastings III, of China; and four grandchildren.