SPEND A MINUTE with Donna Sawyer, 67, and her identical twin sister, Dianne Senechal, and you understand why their weekly gardening show on Saco River Community TV has developed an almost cult-like following.

Think Lucy and Ethel filming their own television show and you get the picture.

Sawyer and Senechal — better known to their viewers as “Grammie Donna” and “Miss Dianne” — have become local celebrities in Buxton and the five other York County towns where their show, “Garden Thyme,” airs. They’re still not sure what all the fuss is about.

“I really can’t put my finger on it,” says Senechal. “Our kids don’t really care for it. The kids think we’re crazy.”

It’s the crazy that viewers seem to love.

They do the show by the seats of their trademark overalls, working without a script.

On a hot, humid morning in August, the sisters are standing in Michelle Gardner’s front yard in North Waterboro. Gardner is an avid composter, and “Garden Thyme” is featuring her in a show about composting with worms. She’s a fan and thrilled to be this week’s guest.

“I think they’re a riot,” says Gardner. “They look like they have so much fun, and you learn these little things you never would have known.”

Sawyer, who’s doing the videotaping, suddenly stops shooting, grabs a large white bath towel and drapes it over her head, all but covering herself and the camera. It’s her “invention” to block out the sun so she can see the viewfinder.

“Just call me Ansel Adams,” comes a muffled voice from under the towel.

Senechal bursts out laughing.

Minutes later they’re laughing again as the camera begins slipping off the tripod and Sawyer dives to grab it, headphones askew, seconds before it hits the ground.

“You can see why we don’t get paid,” says Senechal, with a shrug.

HGTV this isn’t. And that’s the charm of “Garden Thyme.”

Sawyer and Senechal have gardening in their blood. They grew up with seven siblings on a dairy farm in the small Waldo County town of Swanville, where they were responsible for taking care of the vegetable gardens. (Their accent is unmistakably Down East — but when you mention it they both say, “What accent?”)

After graduating from college, the sisters moved to southern Maine to raise their families. They worked in the insurance industry for many years and then got jobs in their local town offices — Sawyer in Standish and Senechal in Buxton. It was at the Buxton Town Office that the Saco River Community TV station manager, Patrick Bonsant, “discovered” Senechal.

“I thought she was funny,” says Bonsant. “And I was after her to do a talk show, any kind of show, really. And then she came in and said, ‘My sister has this soil recipe.'”

“Garden Thyme” was born.

“They have brought so much joy and laughter to this station,” Bonsant says. “Public access stations very often feature very serious talking heads and serious issues, and to have these two come in and do the kind of show they do is a delight.”

Bonsant, who edits the show — frequently leaving in “bloopers” — taught them how to use the station’s video camera.

“He gave me some general instructions,” says Sawyer. “‘Don’t move it fast, and get some outtakes.’ And I said, ‘What’s an outtake?'”

They shot their first show in the spring of 2009.

“I was flabbergasted when I saw that first show,” says Senechal.

“It was really good!” says Sawyer, laughing.

“I couldn’t believe it,” says Senechal.

The second show, though, didn’t go so well.

“The third one flopped,” Sawyer says.

By now they’re both howling with laughter.

They figured they’d keep going until they got it right. Now, after six seasons and more than 100 shows, they have their down-home, no-frills routine down pat. (An archive of episodes can be viewed at bit.ly/1lM549y.)

They’ve covered everything from growing hostas to pruning apple trees. And they’re having the time of their lives.

“People need to enjoy life to the fullest,” says Sawyer, “and I would say that the two of us have just got the world by the tail.”

They retired from their full-time jobs a few years ago. This gig is simply for the fun of it.

“There’s two reasons the two of us do this show,” says Sawyer. “The first is we want to teach people how to grow flowers, plants, perennials. … The second thing is to have fun.”

Sawyer and Senechal are the first to tell you they don’t consider themselves comedians or “movie stars.” They sum it up best in their traditional sign-off, which they happily demonstrate.

“And remember,” they say, pretty much in unison, “we’re just two old ladies in the backyard trying to teach you how to garden.”

That’s a wrap.