OAKLEY -- Bundled against the winter chill, eight teenagers had gathered on an overcast Sunday afternoon to spend a couple of hours moving large mounds of wood chips into place at the far end of campus.
They shoveled the mulch into wheelbarrows and began spreading it over the grassy spot they'll be transforming into an outdoor classroom as Freedom High School teacher John Sierra unrolled the landscape design plans to point out features: Opposite the greenhouse will be an approximately 8-foot-wide fish pond with a rock waterfall and a pump powered by solar energy. A pergola will be erected near the center of the garden; nearby, herbs will grow in an artfully arranged spiral.
And around the perimeter will be "food towers" -- planters fashioned from plastic drain pipes standing on end that have been drilled with holes and stuffed full of soil -- sprouting edibles such as tomatoes and strawberries.
"You get to grow your own food ... naturally grown food with no bug spray," said 17-year-old senior Brandon Kudlik, who turned out to help members of the campus club that will be investing most of the sweat equity.
"Not only are you working hard, but you're learning a lot about native plants," he added.
And that's one of the goals Sierra has for the approximately 6,000-square-foot grassy plot that he and students will be landscaping over the next few months.
He and fellow teacher Susan Warren came up with the idea for the garden;
"The whole reason I became a teacher was so I could build an awareness of the world around us," he said.
In getting their hands dirty and seeing the fruits of their labors -- literally -- students will come to appreciate nature more than if they simply read about it, he said.
"There's so little redeemable value from a textbook. It's just memorizing information to regurgitate on a test," Sierra said.
Senior Ashley Castaldi says she'd be working on the garden even if she didn't receive the community service credit required to graduate.
"I don't go out to the mall -- I don't really spend a lot of time doing that kind of thing," the 17-year-old said.
Creating a garden from nothing, however, is not only interesting but has educational value, she said.
Work on the garden began Dec. 8, and he's aiming to finish by the April 14 deadline for claiming an approximately $1,000 rebate from Contra Costa Water District, which tries to maximize its limited supply by offering the public financial incentives for replacing lawns with drought-tolerant plants.
Between now and then, members of a campus club that encourages stewardship of natural resources will be spending part of their weekends hammering together planter boxes from heavy wooden planks that the East Bay Regional Park District donated from a bridge it replaced.
They'll be following a landscape design that some UC Davis biology and horticulture students drew up for them with a $5,000 grant from the California Native Garden Foundation.
The plans call for adding to the rosemary bushes, lavatera and tall fescue grass they've already planted, putting in not only vegetation found along the banks of the Delta but greenery indigenous to other California ecosystems, including the desert, grasslands and oak woodlands.
Sierra's shopping list is rife with fanciful names: There's the Baja fairy duster, our Lord's candle and sticky monkey flower, as well as the fool's onion and pixie delight lupine.
A foundation along with a Brentwood group of gardening enthusiasts will provide most of the plants as well as cuttings for students to propagate in the greenhouse that some students built over the summer. They've already used the enclosure in experiments growing beans, tomatoes and sunflowers from seeds.
Sierra's hoping that the project will bring in more money so he can include elements that otherwise might be out of reach, such as a computerized irrigation system that uses moisture probes in the soil to determine when and how much to water.
He's on the way to accomplishing that: Sierra recently won a camcorder, laptop and editing software for his students when the undertaking was chosen as a semifinalist in a national competition designed to foster young people's interest in science, math, technology and engineering.
His students now will use the camera and computer to chronicle their progress on the garden and then enter the video in the next stage of the contest, which will end with five schools winning $110,000 each.
Contact Rowena Coetsee at 925-779-7141. Follow her at Twitter.com/rowenacoetsee.