After 45 years of teaching in the Oak Harbor School District, Mike Radach reversed roles this spring when he got a quick lesson in growing giant pumpkins from his son.

Matt Radach, whose interest in growing massive pumpkins sprouted five years ago, gave his dad a small plant that he started indoors from a seed, then added a few pointers.

Mike Radach found a spot near a cedar tree in his Oak Harbor yard in May, stuck the plant in the ground and then watched as nature took its course.

“It was just this little seedling,” Mike Radach said. “Then I babied it along in the cold of May and June, and then it got nice and warm in July and August.”

Months of nurturing and regular sunshine have turned Radach’s pumpkin into a sight that causes cars to slow down in his Oak Harbor neighborhood.

At roughly 400 pounds, Radach’s pumpkin isn’t expected to be the largest at the Whidbey Island Giant Pumpkin Contest Saturday, Oct. 11, at Coupeville’s Harvest Fest.

But for a rookie effort, it’s something to behold.

“I think he did really good for his first year trying,” said Matt Radach, 1997 graduate of Oak Harbor High School who now lives on Camano Island. “I was really surprised at how big it got.”

The younger Radach is somewhat of a giant pumpkin aficionado, having grown pumpkins in excess of 1,000 pounds.

He started getting serious about growing giant gourds after curiosity led him to purchase some giant pumpkin seeds from a farmers supply store in Stanwood five years ago.

His first year, a seed produced an 80-pound pumpkin, which triggered a competitive drive.

“I said, ‘I can do better this,’” Matt said. “I started researching on the Internet. The next year, it was 441 pounds, and it built from there.”

Matt Radach grew three giant pumpkins in his Camano Island yard this year. One of them, a 1,223-pounder, placed fifth during a weigh-off at the Washington State Fair in Puyallup in September.

“This was probably the best season, as far as weather, we’ve had since I’ve been growing,” he said.

Warm, sunny weather is only part of the successful recipe for growing record-setting giant pumpkins, according to Matt Radach, adding that temperatures in the high 80s tend to be ideal, but any hotter, can be detrimental.

Serious giant pumpkin growers test the acidity or alkalinity of a soil, start the plants indoors, provide adequate space and fertilize and water regularly.

Mike Radach initially didn’t follow any of these tips, aside from amending the soil with a little manure, his son said.

He found a mostly shady, 10-foot-by-10-foot spot for the patch in his side yard near two trees and a public sidewalk.

Mostly hidden in a jungle of vines and leaves for most of the summer, the vine was cut and the pumpkin propped up on platform over the weekend for the neighborhood to see from Fairhaven Drive.

“I’m getting a lot of comments now,” Mike Radach said.

Mike Radach said mild curiosity turned a little more serious once a gourd appeared and started growing.

He started watering the pumpkin with warm water and gave it kelp fertilizer and lopped off the top of his trees to provide more sun.

“To me, all you do is put the seed in and let God do the rest,” Mike Radach said. “Give it water, provide nutrients and the light that it needs, and it just goes.

“I’m really amazed at how much it grew, this being the first time.”

Starting with the right seed is the most critical factor, Matt Radach said.

He networks with other giant pumpkin enthusiasts, including fellow members from the Pacific Northwest Giant Pumpkin Growers, and exchanges seeds.

“It’s all about the genetics,” he said.

At HarvestFest, which marks with the final Coupeville Farmers Market of the 2014 season, the Giant Pumpkin Contest also will offer prizes for the prettiest and ugliest pumpkins as well as the largest zucchini.

The contest, limited to Whidbey Island residents, will run from 11 a.m. to 1 p.m. in the space next to the Coupeville Library.

Supported by a grant from the Coupeville Festival Association, the contest is in its 19th year, with the largest pumpkins often delivered by Coupeville’s Lee Roof and Phil Renninger.

Reninger holds the Whidbey record with a 1,016-pounder.

“We may have some really big ones this year as the weather was quite good,” said Roof, who organizes the event.

The state record for a giant pumpkin is 1,791 pounds, grown last year by Joel Holland of Sumner.

The world record is 2,102 pounds, nurtured by Benji Meier of Pfungen, Switzerland. That record was set last week.

For those interested in growing a giant pumpkin, seeds are mailed out by contest organizers in March.

In Mike Radach’s case, his son got him started with a seedling.

It came from a seed of a pumpkin grown in Southwest Washington that weighed more than 1,400 pounds.

“He germinated a whole bunch in March and gave me one,” Mike Radach said. “That’s basically how this whole thing started happening.”