Jim Groverman’s giant corn maze along Highway 101 in Petaluma started out more than 20 years ago as a bit of an accident. After harvesting the ornamental corn at his Sonoma plot the year before, he cut a path through it and realized people rather liked making their way through the giant stalks.

The following year, he decided to try it on a larger scale in Petaluma.

That first year, the 2.5-acre plot made a splash. A television crew from Sacramento flew a helicopter out to get an aerial view of the maze, and the story hit the Associated Press wire. Eventually, someone mailed him a newspaper clipping about the Petaluma plot — from Germany.

“I mean, nobody had really done them, so after that it really started taking off,” said the 55-year-old farmer.

Each year since then, the maze has grown. This year’s, the attraction measures 4.5 acres with 5-foot-wide paths, created by Groverman with little advanced planning and nothing more than a shovel used to clear the stalks their earliest stage of growth.

“I break it down so it’s smaller, and then I work on each section and connect them,” he said. “And then you’re done. I mean, it takes a while. This year, it took me seven full days to do it.”

The cost to enter is $6 per person during the day and $9 at night. Aerial maps are also available of the maze, he said. “We joke with everyone that they’re $1 at the entrance, and they’re $5 inside,” he said, laughing. “It’s just having fun.”

And while he tries not to make the maze too hard, he doesn’t want it to be easy, either.

Still, every year people get lost inside, and employees have to listen for them to help guide them out. Groverman couldn’t say how many times that happens during a season.

“You want people to be able to succeed, but you don’t want them to get through too fast,” he said. “There’s kind of a balance.”

For more information on the maze, go to petalumapumpkinpatch.com.

You can reach Staff Writer Christi Warren at 707-521-5205 or christi.warren@pressdemocrat.com. On Twitter @SeaWarren.