Remember that scene in Woody Allen's "Sleeper" where he happens on a patch of giant vegetables?

You can have the same experience next week in Longmont at the Flower Bin. The nursery has become a local hub for growers of giant pumpkins, sponsoring a contest with a $500 first prize. Growers bring their prize pumpkins to be weighed Oct. 11.

"People bring their coolers and their lawn chairs and umbrellas and sit out and watch the weigh-offs," says Mike Weakland, whose family owns Flower Bin. "Everybody cheers when a big weight gets announced."

Last year's winner was in the 800-pound range, huge for Colorado, which has caught onto the giant pumpkin growing craze in the last few years. For the first time, the Flower Bin contest is part of the national contest, and the winner will be entered on the Great Pumpkin Commonwealth, which certifies giant pumpkin winners. Colorado giant pumpkin fans may have a way to go, however. Pumpkins as large as 1,600 pounds have been grown on the East Coast, Weakland says.

How do you grow a giant pumpkin?

"Half of it is genetics. Half of it is culture," says Ryan Schmitt, Flower Bin greenhouse manager, adding that every grower has his own closely guarded secrets.

"Some people have particular ways to start seedings. Some people start early. Some people like a certain type of potting mixture. Some people put heating cables in the ground where they're going to be growing the pumpkins," Schmitt says.

Most serious growers buy seed from previous contest winners for as much as $15 a pop.

You also need some serious space. One pumpkin needs about a 30-foot-by 30-foot space says Schmitt, adding that the space is filled by the vine with huge leaves.

"Small children can get under them," he says.

Chris Sabol, a self-described Longmont backyard gardener, is also a sometime giant-pumpkin grower.

Last year, she grew a 500-pounder, which she named Maxine. And she once grew a 660-pound pumpkin, winning second prize in the Flower Bin contest.

"You have to be a little obsessed," she says.

Sabol grows her big veg organically, adding copious amounts of material to the soil -- kelp, cow manure, bat guano -- sprays them with foliar calcium, and uses liberal amounts of organic fertilizers, too.

And water.

"If you've got a big one, it can gain 20 or 30 pounds a day in August," she says.

She estimates it cost her about $600 to raise her prize winner.

"I won $300 at the contest, so I cut my loss in half," she says. "You can spend as much as you want to. I think I got off cheap with $600.

Contact Camera Staff Writer Cindy Sutter at 303-473-1335 or sutterc@dailycamera.com