Singer Jack Johnson drew thousands to the Waikiki Shell yesterday for the fourth annual Kokua Festival, but a slew of environmental educators and organic food vendors kept the crowd occupied until the North Shore musician with a worldwide following took the stage.

A few hours before the concert started, hundreds had gathered at the Shell to try free samples of organic yogurt, eat vegetarian burgers and find out about the latest advances in biodiesel. At several booths, children created art out of recycled materials, from discarded CDs to shells.

Greg Beardsley smiled broadly as he watched his 8-year-old daughter, Emma, make a Hawaiian game out of scraps of cloth, seeds and paint. Beardsley and his daughter flew in from Lake Tahoe for the show. It's their second year at the festival.

"I just like the positive message," he said. "Everybody's here for the same reason — the right reason. We're just trying to overcome our throw-away habits."

The festival, which benefits the Kokua Hawai'i Foundation, stresses environmental friendliness and sustainability.

And its organizers, including Johnson, practice what they preach: Next to nothing is wasted at the festival, from leftover food to water bottles.

All of the disposable forks, knives and plates attendees used were biodegradable. Leftover food was kept and will be used as slop at O'ahu pig farms. Recyclable cans and bottles were collected and will be redeemed to benefit charity. And rather than having people buy bottles of water throughout the day, water stations on the grounds offered to fill up bottles for free.

"Green is the way to go," said Makaloa Yim, a member of the Kamehameha School Tree Huggers Club, which volunteers annually at the festival. Yim manned the water station yesterday with fellow club members, filling up thousands of water bottles throughout the day.

At the keiki booths, artist Kevin Seid helped kids make yo-yos out of discarded CDs.

Seid, who makes art out of recycled materials and is on the board of O'ahu Arts Center, said the festival is all about educating people about the little things they can do to help save the planet. "It's teaching people, working with kids, getting them to think about recycling in a very creative way," he said.

In addition to being urged to recycle, the more than 8,000 people who attended the show yesterday also were encouraged to carpool, walk, bike or take an electric-powered trolley from Kapi'olani Community College to the Shell. Many followed the advice, leaving their bikes in a special gated area in the parking lot or packing into cars.

Mimi Verhoeven and Colette Canady carpooled to save gas. The two said they love Johnson's upbeat vocals, but also appreciate his dedication to sustainable living.

"I like that he's promoting environmental issues," said Verhoeven, a 27-year-old King Intermediate School teacher, sitting in the shade with her friend.

The festival continues today, Earth Day.

In addition to Johnson, the concert includes performances by Eddie Vedder, Ernie Cruz Jr., Matt Costa and The Girlas.

Though Johnson didn't take the stage until 8 p.m. yesterday, he did a special performance near the keiki booths about 3 p.m., inviting children onto a small stage with him to sing along. The performance delighted children, their parents and a throng of onlookers filing past to check out the booths.

Reach Mary Vorsino at mvorsino@honoluluadvertiser.com.