About once a month, a growing contingent of farmers, food activists, office workers and the unemployed chooses a small farm somewhere around the Triangle and puts a serious dent in the owner's to-do list.

More than 50 volunteers showed up at Okfuskee Farm, near the northwest Chatham County community of Silk Hope, last Sunday morning. They spent the day building planting beds, moving mulch and hauling timber.

For many, it was a way to get their hands dirty and act on their beliefs about local food.

"If you want to eat local, healthy food, you can't wait for someone else to do it," said Nick Fox, an engineer with Piedmont Biofuels. "Someone's got to build ... the infrastructure."

Fox moved to the Triangle from Rhode Island last winter, drawn partially by thearea's strong local food scene. He soon joined Crop Mob, a group founded by farmers in 2008 to bolster local agriculture.

In its early days, the founders met at one another's farms and shared a meal; work isn't so hard when it's a social event, and they were tired of pushing their cause in boring meetings.

Now, the idea is spreading and drawing people who probably wouldn't have much use for a pitchfork otherwise. Over the months, word of mouth and media exposure has helped Crop Mob draw almost 300 people to its e-mail list. More than 40 people show up at a typical event.

Sunday, dozens of people combined to put in hundreds of hours of labor. At the edge of the farm, they hauled log after log from the woods while a photographer with The New York Times snapped pictures for an article about the local-food movement.

The volunteers also built hugelkultur [a German term] beds, which are raised beds of rotted wood that eventually enrich the soil.

Some volunteers already work on farms or are studying agriculture, including 20-somethings trying to make their own small farms thrive. The night before, the laborers gathered for a party and a campfire. On Sunday, Vimela Rajendran and Angelina Koulizakis served homemade food, such as venison stew, sourdough pancakes and bakalava, for free.

It made sense, said Koulizakis, because her Pittsboro restaurant, Angelina's Kitchen, relies on local farmers as much as it can.

"These are the guys that grow the food," she said.

Rob Jones, a founder of the group, sees the roving work parties as a modern, Internet-connected take on the agrarian culture that faded with the industrialization of farming. In a tough market, crop mobs can give small farms a shot in the arm and connect them to potential customers.

"There's a need for community in this kind of system," Jones said.

Plus, Jones said, many modern farmers in the area did not grow up farming - for them, a crop mob is a way to find customers who are also willing to work the fields.

The hosts of Sunday's mob are new farmers themselves. Bobby Tucker, 27, and his parents bought the 20-acre Okfuskee Farm, where they now raise fruits, vegetables and livestock, about a year and a half ago. For his father, Joe, it was a chance to return to fond childhood memories of the farm.

For Bobby, it's more than a hobby. He could spend decades trying to perfect a sustainable farm, he said.

"It's a lifestyle. It's a political statement," Tucker said. "It's trying to reconnect with your food."