For Russ Pingrey, the race to harvest begins in April with a small seed in a damp paper towel tucked inside a plastic bag.

Within 24 hours he gets a shoot, which he gently pots in soil on his Rincon Valley property. By late April the small starts are planted in the ground beneath a hoop house, where they are coddled for five to six months, even as they grow into Goliaths of the plant world.

A letter carrier by day, Pingrey leads a double life as a competitive pumpkin grower, a pursuit that costs him several thousand dollars a year in water, soil, amendments and transportation to autumn weigh-offs. His fantasy is to grow the world's largest pumpkin, a title now held by Ron Wallace of Rhode Island, who broke the 1-ton mark with a 2,009-pounder last year.

Pingrey is one of up to 100 growers, both amateur and professional, who will compete for ribbons and prizes at the National Heirloom Exposition Tuesday through Thursday, Sept. 10-12, at the Sonoma County Fairgrounds.

Last year, the 3-year-old event drew nearly 15,000 "pure food" enthusiasts from across the nation and overseas to show off, celebrate, ogle, consume, learn about and hopefully help preserve the world's astonishing variety of fruits, vegetables and flowers.

"It's a reconnecting of everybody at once with a different part of the food experience, from the people that tell the stories to people selling fresh hot food, clear back to the people who are saving the seed," said Jere Gettle, founder of Baker Creek Heirloom Seeds of Missouri, which spearheads the event and owns the Petaluma Seed Bank.

"There's an amazing amount of interest, not only here but internationally," he added. "I've talked to people from Europe, Central America and various other places."

Miriam Ahmad may have the distinction of traveling the shortest distance for the expo. She will assemble a choice selection of her home harvest and bring it virtually across the street from her Bennett Valley subdivision.

This is the third year the Santa Rosa homemaker has created an eye-catching display of her backyard bounty, from gangly sunflowers to live plants in containers and picked fruits, veggies, herbs and flowers.

"The point is to show people what they can do on their decks," said Ahmad, who has filled her small yard with raised beds and containers of edible plants. "I try to emphasize that if you can grow a potted plant, you can grow food."

She calls her display "The Edible Backyard." Even the flowers are consumable. Surrounded by a sunflower curtain and overflowing with pots and baskets of beautiful flowers and produce, the organic edible garden last year took a third-place prize for best display. She didn't even know it was in competition, so the ribbon was a pleasant surprise.

It was her inhospitable clay soil that prompted Ahmad to grow everything in containers, beds or pots. Her urban farm produces not only plenty for her own kitchen, but enough for neighbors, too, who receive little gift bags on their doorsteps.

Pingrey is growing not to eat, but to astonish. He embarked on his hobby when he first bought his property 11 years ago. The first year, he "failed miserably," Pingrey said. All his plants died within a few weeks. The next year, after much research, he better prepared his soil and grew a 726-pound pumpkin, "the biggest thing in the world to me."

Since then he's doubled that, growing a 1,504-pound behemoth. Last year he took first place at the Sonoma County Harvest Fair and second place at the Heirloom Expo, which awards $1,000 for first place.

Because weigh-offs fall on different weekends, he has to time his pumpkins to reach maturity at different times — each needing 100 days from pollination, which he does by hand.

The secret is not only in the soil, water and careful culling, but in the seed itself.

"The best way to grow bigger pumpkins is to use seeds with a proven track record," said Pingrey, who spent $80 this season on a single seed, which so far has produced the biggest pumpkin in his patch.

Pingrey knows that growing a record-buster probably won't happen. The East Coast's warm nights are ideal for pumpkins, which grow at night. Right now the man to beat is California's record holder, giant vegetable grower Leonardo Urena of Napa, who produced a 1,704-pounder. He's entered at the Heirloom Expo.

You can reach Staff Writer Meg McConahey at meg.mcconahey@pressdemocrat.com or 521-5204.