Sandy Bauers / The Philadelphia Inquirer

PHILADELPHIA — Ken Finch delights in asking people to recall happy childhood moments spent outdoors.

Invariably, they involve nature: climbing a favorite tree, wading in a stream, catching fireflies in a jar.

But this works only when his audience is older than about 30. If they’re younger, they were born after a divide — the time childhood in America changed. For the worse.

No longer did they run outdoors on a Saturday, coming home only when the streetlights went on.

More and more, they stayed indoors. Research shows children now spend 1 percent of the day outdoors, and 27 percent with electronic media.

There are a lot of reasons — urbanization, parental fears, more structured activities, and so on.

But it’s bad because being outdoors confers many benefits. Studies have shown that kids gain coordination just in navigating the uneven terrain. They learn decision-making skills and gain confidence. Vigorous play counteracts obesity.

It’s not just about the kids. It’s about the planet. Kids’ relationship to nature will influence everything from what kind of car they drive to how they vote when they are adults.

So now, groups are advocating a return to the outdoor childhood. Their mission: No Child Left Inside.

In October, the National Wildlife Federation announced a goal to move 100 million kids “from their indoor habitat.”

Finch is head of Green Hearts, a national nonprofit that wants to restore the bonds between children and nature. Recently, he spoke at the Schuylkill Center for Environmental Education in Philadelphia’s Roxborough neighborhood.

His talk — spiked with cartoons, such as the one with adults in a car exclaiming, “Look! Free-range children!” — was a plea to get kids back out in nature. And not just in nature, but interacting with it (Find tips for parents at

Too many natural areas have too many rules, he said. Don’t run. Stay on the trail. Instead, what kids need is “rough land that adults don’t care about, where you can whack a tree with a stick.”

He was in the right place. The Schuylkill center, known for its nature programs, will begin a nature preschool in the fall.

Gail Farmer, director of education, said it was always assumed that kids loved the outdoors, and teachers could build on that.

Not so anymore. Said Finch, “We can teach kids all about nature, and if they don’t give a damn, it won’t matter.”

The new preschool won’t have the kids studying letters on Monday and colors on Tuesday. They will get dressed for the weather and go explore “whatever captures them,” Farmer said.

Friends School Haverford found out pretty much the same thing in 2007, when a construction project created a large puddle. Kindergarten students who happened to be outside for a fire drill were intrigued. Their teacher, Ann Ward, decided to make a learning tool out of it. Through the seasons, over the years and across the curriculum, the kids measured the puddle, identified the creatures that visited it, the plants that grew in or near it. A “Puddle Newsletter” was begun.

“Maybe it’s not the playground” that’s important, Ward concluded. “Maybe it’s the edges.”

Now more a wetlands — with birdhouses and native plants — the puddle is still a magnet.