In early October, Michelle Obama and students harvest the White House Kitchen Garden for the final time while she is first lady. (Michael Reynolds/European Pressphoto Agency)

Since the early 1970s, Jim Crawford has grown organic produce at his southern Pennsylvania farm, so when a chef friend asked if he would help a Washington resident with her new home garden, the task seemed easy enough.

The catch? The lady in question was the first lady, and the garden he was guiding into life suddenly would become known around the world. Michelle Obama, a gardening newbie, later confessed that its installation on the South Lawn of the White House in March 2009 made her nervous. “I was, too,” Crawford said. “It was a brand new garden out of nothing, and being in the spotlight like that, you really want it to be successful.”

Seven and a half years later, the consensus is that this essentially homespun fruit and vegetable garden — a French chateau potager, it is not — not only fed White House staffers and world leaders alike but became a potent symbol for the central cause that defined Michelle Obama’s public life in Washington, what she calls “this healthy-eating stuff.”

But there is a season for everything. The garden shrinks in autumn retreat and the days of the Obama administration grow shorter. The question in the crisp fall air: What happens now to her Let’s Move campaign, and what of the garden itself?

The first lady sought to reassure more than 200 of her Let’s Move campaign partners at a dedication Oct. 5, unveiling a more permanently structured White House Kitchen Garden with paving, outdoor furniture and an arbor in a garden that has almost doubled in area since the spring. The seed merchant W. Atlee Burpee & Co. announced a $2.5 million gift for its continued care. The day after the dedication, Michelle Obama held her final harvest party in the garden with grade-schoolers.

A new arbor adorns the entrance to the White House garden. A month out from Election Day, the first lady’s office unveiled an expanded and improved garden, with the hope that it will endure regardless of who takes office come January. (Manuel Balce Ceneta/AP)

A future president is free to return it to grass, or even a putting green, but its more permanent features may discourage that. The first lady said, “I am hopeful that future first families will cherish this garden like we have.”

As for the causes of fighting childhood obesity and improving the diet of all Americans, “I intend to keep working on this issue for the rest of my life,” an emotional Obama told the assembled crowd.

A spokesman for Hillary Clinton said she intends to keep the garden if she is elected president. (The Trump campaign has not responded on the topic.)

Inside the Office of the First Lady, the Let’s Move campaign is run by a staff of four that goes away with the change in administration. But the movement’s organizational framework outside the White House “was built to last. The work will continue,” said Deb Eschmeyer, the executive director. The Let’s Move initiatives include putting salad bars in schools, promoting exercise regimes and creating community gardens in conjunction with other organizations and local partners. Some of the work will continue within government agencies, but the Washington-based foundation, Partnership for a Healthier America, will function as the clearinghouse for more than 200 private-sector partnerships and foundations that support the initiatives.

Historian Barbara A. Perry said that at 52, the highly popular first lady has the prospect of years more of public service, and that other first ladies achieved as much or more after leaving the White House as they did when their husbands were in office. Perry noted that after Franklin D. Roosevelt died, Eleanor Roosevelt became a champion of human rights and represented the United States at the United Nations, becoming what President Harry Truman called “the first lady of the world.”

“Mrs. Obama will have 30 to 40 years as a former first lady, to the extent she wants to use that power and influence,” said Perry, a professor of ethics and institutions at the University of Virginia’s Miller Center. “She’s obviously a socially conscious person, so I suspect she’ll continue in this role and pick up others.” Obama has other causes, too — one bringing a spotlight on wounded troops and their families, and another to improve access to education and opportunity for girls and young women in developing countries.

The first lady has said that she was driven to create the White House Kitchen Garden and develop initiatives in childhood nutrition because of worries about the diet of her own daughters, Malia and Sasha.

The garden more than doubled in area over the years, and its corner of the South Lawn also includes an apiary and a pollinator garden for bees and other insects.

A flower bed is mixed with vegetables to attract more bees to cross-pollinate plants at the White House Kitchen Garden. (Manuel Balce Ceneta/AP)

Many of the causes Obama championed had been adopted by others earlier, including school gardens, locally grown organic food, and addressing the dietary challenges of the urban poor. The Pennsylvania Horticultural Society, for example, has had an active urban greening and community gardening program in Philadelphia since the 1970s.

But no one has brought all these issues together as effectively as the first lady, and many believe she has had a key role in their success. Noting advances in the past six years, Obama said that 50 million schoolchildren had access to healthier meals and snacks at school and 11 million were getting daily exercise. Fresh fruit and vegetables are widely available in fast-food restaurants and even convenience stores, and more than 8 million people in poor neighborhoods are now able to buy healthier food.

“She has done it in a very nonprescriptive way,” Eschmeyer said. “She’s created almost this Public Health 3.0 version of how you meet families where they’re at.”

“There are a lot of players doing a lot of things, but before the public will support anything, they have to understand there’s a pressing problem to be addressed. She helped with that,” said Kelly Brownell, dean of the Sanford School of Public Policy at Duke University. “The fact she’s committed to her own family and American families overall is pretty clear when she speaks about these issues, and that gives her great credibility.”

What seemed at first a garden dedicated to the principles of the local food movement soon shifted to encompass the broader issues of childhood obesity, health, nutrition and exercise, particularly in impoverished city neighborhoods. It’s conceivable that Obama could have orchestrated her Let’s Move efforts without the garden, but not as successfully: Even in the digital age, people need a physical embodiment of an idea. The garden “set the tone at the beginning,” said Washington restaurateur and local-food champion Nora Pouillon. “That was the first thing she did.”

In the Bronx, Toby Adams guides 7,000 schoolchildren each year through the New York Botanical Garden’s family garden, and 18 months ago took two of them as guests to a spring planting event at the White House. A week earlier, they had helped to put in transplants, so when they came to Washington, they decided to help the first lady with the lettuce and broccoli. “She was letting them teach her how to dig a proper hole,” he said. “She was just absolutely having a blast with the kids.”

If the role of the White House Kitchen Garden diminishes with Michelle Obama’s departure, its place in history seems secure. “Being such a positive person, and using the garden in a way that shows you can have the tools for yourself, is a great message,” Adams said. “She leaves a strong legacy.”