First Lady Michelle Obama and students planted vegetables at the White House Kitchen Garden on the South Lawn on Tuesday as part of her American Garden Tour. (Reuters)

Next year, if President Trump paves over the White House garden for his helipad, we will remember its bushels of kale, its bulbous turnips, its symbolism of a happy, healthy, sustainable America that ate right and stayed active.

“This is my baby,” Michelle Obama said on the South Lawn on Tuesday. It was her eighth and final spring planting, but “hopefully,” she added, “this will not be the last” one ever.

Maybe it will, maybe it won’t. Hillary Clinton’s husband is a vegan, so maybe Farmer Bill will be a thing. It’s hard to imagine Melania Trump in the dirt, on her hands and knees with schoolchildren, as Obama was on this cloudless afternoon, but we’ll keep an open mind.

For now, though, Obama’s garden is as big as ever, at 1,700 square feet. “Churchill” brussels sprouts and “Kentucky colonel” spearmint grow there. There also is garlic and fennel and shallots and endive. There are schoolchildren from Louisiana, Colorado, Wisconsin and Northwest Washington — free child labor enlisted to press seedlings into the dirt and to learn, over and over, that vegetables are good for you (except radishes, which are an abomination).

About 1:30 p.m. the first lady literally jogged into the garden area. It was 43 degrees. She was not wearing a jacket.

“You might be more interested in eating your vegetables if you know what they look like,” Obama told the students. A bitter breeze nipped at her bare ankles. Some of the students covered their ears with mittened hands. FLOTUS was all pep.

Malik Robins, 11, of New Orleans and Erin Hinson, 10, of Washburn, Wis., help the first lady plant vegetables. (Pablo Martinez Monsivais/AP)

The White House is proud of its garden, supposedly the first of its kind since Eleanor Roosevelt’s in 1943. The vegetables wind up in dinners for the first family. Almost 500 pounds of them have been shipped to homeless shelters. In 2010, they ripened into Obama’s “Let’s Move!” campaign, for which the first lady danced with Elmo and Jimmy Fallon in order to get kids off the couch and to the crisper. She has also nudged corporations to trim salt, sugar and fat from food products.

Tuesday’s planting was an inspiring and wholesome photo-op, and also a way for the East Wing to get certain numbers into the hands of journalists: 2 million children now have “Let’s Move!” salad bars in their school cafeterias (mmm croutons!), and food and beverage companies have eliminated 6.4 trillion calories from their products, or so they say. Reality check: The world is fatter than ever. One-fifth of the global population will be obese by 2025, according to a study released last week by Imperial College London.

And so we defiantly plant mustard seeds with the children, hoping the example ripples forth. There is anecdotal evidence that it has: Obama is on an “American Garden Tour” to visit community gardens that were inspired by hers. On Thursday, she is off to schools in Burke County, Va., and Newark that subsist partially on farmers markets and rooftop gardens.

For an hour Tuesday, though, she was knee-to-knee with students, massaging the roots of cabbage seedlings, making small talk.

“What’s been fascinating?” Obama asked one shy student about his trip to Washington.

“Um, the White House,” the student answered.

“That’s fair enough,” she said.

“Will y’all still get first class?” one student asked her, referring to post-presidency travel, but Obama’s answer was drowned out by the camera shutters of the assembled media.

Six of the students here attended her first planting, back in 2009, when the world was young and innocent. They were in fifth grade then. Now they’re approaching college age.

“We’re proud of you guys growing up,” the first lady told them, patting down some dirt in a cabbage bed. “Growing up. Getting ready to be leaders. So we can retire.”

Ah, the circle of life, and the vortex of politics. The green-thumbed Washington philosopher Chauncey Gardiner said it best: “In a garden, growth has its season. First comes spring and summer, but then we have fall and winter. And then we get spring and summer again.”