In this photo from Oct. 5, 2011, first lady Michelle Obama gets help from fifth grade student Sterling Zapata in filling a basket with peppers in the White House garden in Washington. (Pablo Martinez Monsivais/AP)

One of Michelle Obama’s early worries about life in the White House had to do with a plot of land. Specifically, the new first lady found herself fretting over whether her much-hyped garden would grow.

“I was like any other hopeful gardener with a pot out on the windowsill or a small plot by the back door. I was nervously watching the sky. Would it freeze? Would it snow? Would it rain?” she writes in her first book, “American Grown: The Story of the White House Kitchen Garden and Gardens Across America.”

The book and interviews this week are part of a steady stream of media appearances for the first lady, who is playing a central role in her husband’s reelection campaign.

The garden, which has been a focus of Michelle Obama’s since her husband took office, led to the first lady’s “Let’s Move!” initiative targeting childhood obesity.

“It is definitely a passion — getting our kids in this country eating healthy, helping families make good choices about how they eat and stay active — and this book is a way to talk about our journey but also talk about the challenges that we face as a nation around health,” Michelle Obama told ABC’s Robin Roberts on “Good Morning America.”

In her book, the first lady — and novice gardener — tells the story of planting the first White House kitchen garden since Eleanor Roosevelt’s victory garden. The seed for the garden emerged long before her husband’s presidential campaign, at a doctor’s appointment where the family’s pediatrician pulled her aside and suggested that she might want to watch what the girls were eating.

As she promoted her book, Obama pushed back in interviews Tuesday against criticism that her program is an example of big government dictating what children should eat.

“One in three of our kids are overweight or obese,” she said on ABC. “But this isn’t about government telling people what to do. What we know we need to do is give parents, communities, families the tools and the information they need to make choices that are right for them, and there’s no one-size-fits-all solution.”

The first lady has said often that her anti-childhood-obesity work is nonpolitical, and the book takes the same tone, with recipes from White House chefs, tips for planting a garden, and photos of the first lady with children, vegetables and the family’s dog, Bo. She did not accept an advance for her book, and its proceeds will go to the National Park Foundation for programs that promote healthy eating and gardening and for the continued care of the White House garden.

The first lady also made clear in interviews with ABC and USA Today that she is not interested in a career in politics and will not run for president, though she said, “I love campaigning.”

“I say this all the time — if every American had the opportunity to travel around the country and go into people’s living rooms and talk, we’d understand that we have so much in common and we’re working towards the same goals,” she said.

Despite Obama’s love for vegetables, there’s at least one that won’t be making an appearance in the White House garden under her watch.

“One thing the president and I, we don’t really like, are beets,” she said. “We don’t have beets. We’re a no-beet garden. We believe there’s a beet gene. You either love beets or you hate ’em, and neither of us have the beet gene.”

Staff writer Felicia Sonmez contributed to this report.