It was Dirty Finger Club Day at Linton Springs Elementary School, near Eldersburg.

Out in the vegetable garden — one of a dozen "outdoor classrooms" in the meadows, wetlands and woodlands of school's spacious grounds — Anna Letaw, a volunteer who has been the dynamo behind Linton Springs' Environmental Education Program, was giving a kindergarten class a primer on gardening.

"Oh, look what I found!" Letaw called out as she knelt. "An earthworm .... Can anybody tell me what earthworms do?"

Hands shot up. "They help get the dirty stuff out of the ground so the plants can grow," one little girl offered. .

"They eat the bad germs!" a boy added.

Letaw nodded. "The worms break down the nutrients in the soil and — you're going to love this! — their poop makes the soil healthy," she told them.

Noses wrinkled, followed by a chorus giggles and moans of disgust.

"So what are you down here for, besides playing in the dirt?" Latew asked them.

"Because we're going to plant peas!" a kid shouted.

"Yummy!" added another.

Latew, last year's Carroll County Parent Volunteer of the Year and a Maryland state finalist for the Parent Involvement Matters Award, showed them how to plant a pea by poking her finger in the dirt, dropping in a pea, then squeezing the hole shut.

The kindergartners lined up and took turns planting peas.

Some showed off their dirty forefingers — proof of membership in the Dirty Finger Club — to their classmates as they followed their teacher back inside.

"I'm always concerned that they're going to get bored, but they love it," Latew said. "They get really excited."

The Dirty Finger Club is just one facet of Linton Springs' Environmental Education Program. In addition to the vegetable garden, there is a winter garden with cold frames, a native plant garden and a designated wetlands area with a stream. A new monarch butterfly garden and a $3,000 solar garden are under construction.

"In class they talk about different kinds of habitats, and we bring them out here and show them," said Latew, who is one of several certified Master Gardeners who volunteer in the program.

"Everything Anna does down here she's found a way to tie it into the common core curriculum," added Alaina Haerbig, director of the school's gifted and talented program.

Haerbig, along with fourth grade teacher Megan Dryden, co-leads a student group called the Green Team. "We have tons of science going on down here," she said.

Like Latew, Haerbig has been a prime mover behind the program. It has not only brought a hands-on, ecology-oriented dimension to the academic programs, but has proved therapeutic for some students.

"I had a student who was at an unhealthy weight and he had some behavioral issues," she said. "So I brought him down here to the garden. He got exercise, he ate fresh, organic vegetables and he was willing to work in the garden. It changed his life."