WASHINGTON: Michelle Obama's affection for the White House South Lawn has grown just like the sweet potatoes and carrots she plants there.

During seven years as first lady, Mrs. Obama has often used her family's temporary backyard as a grassy stage from which to promote a lifestyle built around plenty of fresh, nutritious food and lots of exercise.

But to Mrs. Obama, the 6-plus acres of manicured grass and gardens are more than a place to talk about diet and health. It's a symbolic venue for a mother of two from the South Side of Chicago who stepped into the role of presidential spouse with the goal of welcoming more visitors, especially children, to the seat of world power.

"While our family might live upstairs, the president and I know that the White House is truly the 'People's House,'" the first lady said. "It belongs to all of us."

Military families and students are among those given priority at White House events such as the annual Fourth of July picnic. Mrs. Obama is also more consistent than her recent predecessors in using the South Lawn. Most first ladies used the outside grounds for the occasional state dinner, annual Easter Egg Roll or ceremony for a visiting head of state.

Girl Scouts hunkered down in tents for a campout last summer until rain and claps of thunder sent them and their chaperones scampering into a nearby office building. Mrs. Obama said it was the first campout ever held on the lawn.

In 2011, scores of children surrounded Mrs. Obama on the lawn to break the Guinness World Record for the most people around the world doing jumping jacks in a 24-hour period. (More than 300,000 people participated.) The lawn is also where she showed off her hula-hooping prowess, performing 142 turns of her hips during a "healthy kids" fair that same year. Children joined her in 2014 when blue sport bottles were laid out on the lawn in the shape of a water drop, part of her campaign to encourage people to drink more plain water.

Observers say these events wouldn't pack the same punch if Mrs. Obama held them anywhere else.

"Even if those kids are sweating in the sun doing jumping jacks, they only need to look back over their shoulder to see the most powerful house in the world," said Carl Anthony, historian at the National First Ladies' Library in Canton, Ohio.

Another advantage to the lawn? Security. It's behind iron fencing and far removed from surrounding streets and passers-by, though it wasn't always closed off.

Members of the public were allowed on the South Lawn during regular visiting hours that continued into the late 19th century, said William Bushong, chief historian at the White House Historical Association. The nurse maid for President Grover Cleveland's wife, Frances, often took the first family's two young daughters to the lawn during the public hours.

But the situation got a "little bit dicey," Bushong said, when, due to public fascination with the children of presidents, a woman picked up Cleveland's youngest child and "started passing her around." Mrs. Cleveland was "freaked out" and "at that point, they closed the gates," Bushong said.

Subsequent presidents reopened the White House grounds, except during war. Open access to the grounds ended with World War II, Bushong said.