Behind the silo and the cornfields on a farm in Southern Maryland, the bluegrass music began to patter and whirl. Joseph Snyder looked up from his plate of sliced tomatoes when he heard it, and his wife Judy tapped the footrests of her wheelchair with her socked feet, as though remembering a dance.

Campers had been rolling into Leonardtown all week for L'il Margaret's Bluegrass & Old-Time Music Festival, which began Thursday and ends tomorrow morning, so all around the Snyders people were unfolding lawn chairs to get ready for the show. Like the free spirits who followed the Grateful Dead from concert to concert, hundreds of bluegrass fans travel from festival to festival all summer, chasing after the music.

But at L'il Margaret's, the coolers are more likely to be full of homegrown tomatoes and corn than beer, and if someone pulls out a pouch, it's probably pipe tobacco. These are groupies with suspenders, cowboy hats, plaid shirts and trucker caps -- some helping a friend or a parent hobble down to the stage, some sitting on wooden benches and picking at guitars.

Joseph and Judy Snyder met at a dance: He needed a partner, and there she was. Now, going on 50 years later, she can't dance anymore, but they said they'll go to festivals as long as they can, packing his 102-year-old banjo into their pop-up camper in Pennsylvania and hitting the road.

Joseph and Margaret Goddard started the bluegrass festival from scratch 15 years ago. Their sons cut the lumber for the barn-like stage where the bands play. They cleared the hay from a corner of the family's 160-acre farm off Route 5 in St. Mary's County so people could park.

During the festival, Margaret Goddard spends the weekend with helpers in the kitchen, flipping pancakes, stirring chili and slicing stuffed ham that's sold to crowd. Every year, family and friends pitch in, answering phones, putting up hand-painted signs, handing out wristband passes as the pickup trucks come in.

They don't sell alcohol and don't allow coolers near the stage. The Goddards know some people drink inside their campers -- by 2 p.m. Thursday, a grassy patch by one was dotted with blue Miller Lite cans -- but by and large this is a quiet, sober crowd, the Goddards said.

Joseph Goddard met his wife at a country dance in St. Mary's County. They married and had six boys in a row, then two girls. They called the first girl "little Margaret." When she was 21, she died in a car crash.

"She enjoyed music," Joseph Goddard said, with a hitch in his voice, "country music and bluegrass music. She always carried a radio with her. It burnt up with her, too."

After some time had passed, Margaret's parents thought it would be nice to have a bluegrass festival in her honor. The first festival was held about a year and a half after her death, Joseph Goddard said.

At age 72, Goddard is retired from the fire department at the Patuxent River Naval Air Station and his sons do most of the farming. "If I could, I would enjoy dancing," he said. "My knees and all kind of wore out somehow or another."

Over the years, the festival has become more professional -- some of the 15 bands hired this year are well-known on the bluegrass circuit -- and the crowds have grown. Most years, the Goddards said, they draw about 1,000 people. Tickets at the gate today cost $22 for a full day of music stretching from 9 a.m. to 11 p.m. The festival closes with an hour of free gospel tomorrow morning.

People like the Snyders keep coming, year after year, following the music. Joseph Snyder repaired truck transmissions for a living, but many nights he'd play his banjo and call square dances. He helped start a fiddler's convention near his home in Airville, Pa., and after retiring, he paid $500 for a used camper and got serious about getting to festivals.

"I always bring grandpa along," he said, referring to his well-worn banjo gleaming with mother-of-pearl.

On Thursday evening, attendees brought lawn chairs toward the stage as the bands began, some people pulling on ponchos as the rain came. A man took his wife's hand and led her to a clear patch on the dance floor. Their feet shuffled and thumped on the plywood for a few moments.

Joseph Snyder had pulled on rubber boots and was taking down the canopy. He had put his wife to bed and planned to listen from inside their camper for a while. Later, maybe, after the show was over, he'd take out his banjo.

Members of the Jack Tippett band -- Michael Norris, Ed Salada and Meg Cratty -- warm up at L'il Margaret's Bluegrass & Old-Time Music Festival in Leonardtown. Guy Hook of Stewartstown, Pa., picks his banjo with Yvonne Koyzis on guitar while Vernon Barnes listens. Joseph Snyder and his wife, Judy, drive their camper from festival to festival.