Is a year after your publication date too late for a book signing? Not if you’re the first lady.

It was a chipper Michelle Obama who breezed into Politics & Prose Tuesday to greet a crowd of 250 or so fans. “Not so good for standing outside, but really good for gardeners, this rain,” she said with a smile.

Yes, it’s been a year since she released “American Grown,” but it seemed that both the publishing house and the author were hoping to generate some fresh planting-season buzz for the photo-filled account of the White House garden. (Proceeds benefit a National Park Service program promoting gardening.)

And remember — only five shopping days ’til Mother’s Day! “I would buy one for my mom,” said the first lady, “but she already has 10.”

Book buyers line up for their moment with Obama. (Jewel Samad / AFP/Getty Images)

These were serious Michelle fans who turned out, having waited in line at the independent bookstore last week to get security clearance and buy a copy in advance. (Buyers at her appearance at a downtown Barnes & Noble last year jumped through similar hoops.) They waited in line again Tuesday for nearly two hours before she appeared. Their reward: Her signature — sorry, no personalization — and 20 blissful seconds of first lady chit-chat.

But those fleeting moments with the first lady were worth the wait, several customers said as they were ushered out of the store.

One young man volunteered that he would soon finish law school; she asked about his summer plans. A woman shared that two of her three kids are vegetarians; Obama urged her to make sure they’re getting the right nutrients. One fellow confessed that his favorite food is avocado.

“You know who else loves avocados?” she replied. “Sasha.”

And so on. Even a year later, she said her book is still relevant and engaging for all ages. The garden, which has been one of her focuses since her husband took office, led to the first lady’s “Let’s Move!” initiative targeting childhood obesity.

(Susan Walsh / AP) (Susan Walsh / AP)

“I found that my girls really enjoy just thumbing through and looking at the pictures, but slowly but surely they started to actually read what was in there,” Obama said at the start of the event. “And that’s really the hope — that the pictures draw people of all ages in and then they start to read it and maybe start thinking about how to start a garden on their own, because there are many ways to do it.”

As to the timing of the signing — 11 months after the book’s publication — she pointed out the busyness of 2012.

“If you recall, when the book came out we were in the middle of this campaign,” she said. “So we were a little busy.”

10 p.m. This post has been updated

Earlier: Michelle Obama champions vegetable gardens and healthy food in ‘American Grown’, 8/2/12

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