The biggest pumpkin in the world this year weighed 1,818.5 lbs. and came from Wellington, Ontario. But its story actually began in 1986 in Windsor, N.S.

Twenty-five years ago, a Windsor man named Howard Dill patented a pumpkin seed variety he named the Atlantic Giant. Dill was a full-time farmer and part-time mad scientist. Home from the evening’s chores, he’d work for hours at the kitchen table, doodling pumpkins and taking notes on his experiments. He spent years secretly perfecting a new line of super heavyweight pumpkins.

What started as a friendly rivalry with other local farmers at the Hants County Exhibition’s annual pumpkin weigh-off became a full-on obsession by 1980. Before the decade was out, Dill set two records for the world’s heaviest pumpkin. But it wasn’t his pumpkins that made Howard Dill the most famous man in the giant pumpkin world. It was the seeds inside them that, combined with his own genetic crossbreeding technique, sprouted the modern quest for the biggest pumpkin of all time.

Today, 20 generations of competitive pumpkins can trace their roots back to the first Atlantic Giants. This fall, more than 10,000 hobbyists in 14 countries entered giant pumpkin contests using seeds derived from Dill’s. “He is the father of the modern pumpkin weigh-off. There’s not one growing now that doesn’t go back to him,” says Dave Stelts, president of the Great Pumpkin Commonwealth, a nonprofit that sanctions over 80 pumpkin weigh-offs around the world.

Dill died in 2008, but he lived to witness the world’s first 1,600-lb. pumpkin. Now growers are closing in on the 2,000-lb. mark. “He just couldn’t imagine a 1,600-lb. pumpkin. It was beyond him,” says Howard’s son Danny Dill, who runs the Dill Farm with his sister, Diana MacDonald. Today, the farm draws 5,000 tourists a year and sells 2000 lb. of seeds—enough to grow 2.4 million pumpkin plants. Atlantic Giants are tipping the scales in Australia and Finland.

The prospect of a one-tonne pumpkin would have dumbfounded Howard Dill. A quiet and serious man with a seventh-grade education, Dill taught himself about plant genetics by reading gardening magazines. It occurred to him that he could isolate a male and female flower and perform his own pollination ritual to combine the most desirable characteristics of two plants—one with a nice orange colour and one heavy enough to break the back of his hay wagon. When he swept the weigh-offs for three years straight, he knew he had his own genetic imprint.

His real source of inspiration was the farm itself. “He was so particular about what kind of bull he would allow to breed with his cattle. He liked a quiet bull, not a bad bull. He just took it from that to the pumpkins,” says Danny Dill.

Championship pumpkin growers aren’t entering beauty contests. Their ideal pumpkins look more like mutant lumpen marshmallows, their skin a mass of hardened yellow-green scar tissue. The inner walls can be 30 cm thick, decidedly unfit for pumpkin pie—but perfect for a weigh-off.

Today, the Dill seed brand is better known for its pleasing orange hue than its girth. It’s a beginner’s seed, guaranteed to produce a supreme jack-o’-lantern. Like a parent who looks up one day and realizes his children have grown to be taller than him, Dill watched younger growers push their gourds into a different stratosphere using products and techniques he’d never dreamed of.

These growers have invented a few methods of their own, like garnishing plant compost with exotic amendments such as kelp extract and mycorrhizal fungi. No sacrifice is too great for the pumpkin elite, who spend thousands of hours pruning, heating, cooling and sheltering their pampered gourds. They spray the leaves with misted carbon dioxide, and treat them for root rot, fearful of disease. They mail leaf samples to far-off laboratories for analysis, and use the results to decide which additives—including calcium and phosphorous—to apply. Then they stand back and watch as their titanic fruits gain up to around 50 lb. a day.

As each generation of gourds surpasses the last, it produces seeds that form the basis for the following year’s mutant orbs. The seeds with the grandest lineage are much in demand within seed-trading circles and at online auctions. Someone paid US$1,600 for a seed from the 2010 world championship pumpkin, which weighed 1,810 lb. and was grown by a contractor named Chris Stevens in New Richmond, Wis.

Clad in blue jeans and a checked shirt, Dill transcended the role of small-town farmer and became the worldwide ambassador for his Atlantic Giants. He and his homegrown gourds appeared on The Martha Stewart Show, but he also gave his time to every visitor to his farm who wanted to talk pumpkins (or hockey, his other passion). When someone set a new world record, Dill sent a personal letter congratulating him or her on the achievement. He wrote those letters well into his seventies, right up until he died.

Iowa grower Don Young got one of Dill’s letters in 2007, after he grew the second-heaviest pumpkin in the world. He had invoked Dill’s name on Good Morning America, thanking him for his contribution to the hobby. “I should really frame this thing,” says Young, who got into growing giant pumpkins after buying, on a whim, a packet of Dill’s Atlantic Giant seeds at a local garden store. (The seeds are sold at Lowe’s stores in the U.S.)

In many ways, Dill was the last of a breed. Very few champion pumpkin growers are farmers today, but many see themselves as inventors on the land. Stelts, of the Great Pumpkin Commonwealth, grew an 1,801-lb. pumpkin in Pennsylvania this year—but he also grew an eight-foot-tall tomato plant and green beans as thick as carrots, with the same kinds of methods and products he used on his pumpkins. “I’ve got yields now that are just out of control,” he says. “If we can grow an 1,800-lb. pumpkin, imagine what you can do in your garden. To see that translate over to the dinner table is really exciting.”

Windsor has a carved wooden statue of Dill, smiling beneath his baseball cap. But few Canadians are aware of the legacy of the man who passed on his obsessive quest for the perfect seed. Fewer still have seen the family farm, which grows 30 pumpkin varieties and houses cattle in the same old barn, built in 1840, that Dill’s own father grew up working in.

Windsor triples in size over Thanksgiving weekend for the annual Pumpkin Regatta, as 10,000 spectators drive up to watch a few dozen locals row (awkwardly) across Lake Pesaquid in brightly painted, hollowed-out giant pumpkins. (There’s also a motorized competition.) “A couple of women approached Danny and said, ‘What can we do with these pumpkins other than grow them?’ and Danny said, ‘Let’s have a race with them,’ ” recalls Diana MacDonald. The regatta is now in its 13th year.

Danny Dill still has his father’s meticulously detailed notebooks, with their pumpkin snapshots, doodles and descriptions. “He made notes about the stem, the ribs on it,” he remembers. “The pumpkins themselves, he would just sit and look at them.”