Lettuce, bananas and other fruits and vegetables lovingly tended by schoolchildren in campus gardens also can be ripe targets for passersby who "help themselves," as well as for more malicious thieves and vandals. Schools should openly address such incidents as they occur, officials say, so students can be part of positive solutions.

At least 40 percent of the public, charter and independent schools in Hawaii have campus gardens, according to a 2012 survey conducted by the Hawai‘i Farm to School and School Garden Hui. The 168 gardens sit on a total 30 acres of land, engaging 21,577 students and 830 teachers in outdoor learning environments that connect children to the land, encourage self-reliance and provide living laboratories for science, math and other lessons. Some of the gardens also serve as oases of peace, meant to nurture friendship and positive peer relations.

"We hope that the kids who are getting their hands dirty in elementary school in the school gardens will grow up with an interest in nature, and the land and sustainability and farming and the vibrant abundance in all parts of life," said Lydi Morgan Bernal, co-chair of the hui and school garden coordinator for the nonprofit Kokua Hawaii Foundation.

Some gardens have been robbed or vandalized in the past, Bernal said, although she did not have precise figures.

When incidents occur, schools should be open about what happened, quickly clean up any mess, and make or restore signs indicating that the garden plot is a highly valued educational resource, she said. "It’s important to take every instance seriously, to respond quickly and to seek positive solutions that the students can be part of."

That’s exactly what happened when Pauoa Elementary School’s kindergarten garden was vandalized in late August. The school posted a news story about the incident on its website, describing the importance of the lettuce plot and encouraging readers to call in with information: "Let us all join in one voice to prevent this from happening again!"

University Laboratory School, a charter school with several small gardens and an aquaponics system, also has confronted this problem. The gardens promote peace and sustainability, and are the setting for lessons in science and other subjects. Students generally donate what they grow to the hungry, so when fruit and vegetables go missing, they try to gauge whether it was for personal consumption, said Vice Principal Miki Tomita.

"We really talk about it. Is it OK if a person helps themselves, if it’s someone who is hungry? When locks are cut or heavier equipment is stolen, like our vermicomposting equipment was, we report that to the police," she said. "With the food, we talk about it and the students decide. When our banana trees were harvested the students wanted to report that; they didn’t feel like it was someone feeding themselves."

Ultimately, the young gardeners may gain empathy for farmers and ranchers who are trying to make a living by raising and growing food.

"One of the things we learn is that it is sometimes quite difficult to maintain a functioning garden," Tomita said. "So if you scale that up to a farm, it’s pretty clear that it’s even harder."