School Yard Garden Project

My middle schoolers here in Arizona are undertaking a big project~ a schoolyard garden. The garden, which they have named, "The Secret Garden" is in the planning stages. We have some mesquite trees and benches, and a pretty white arch at the entry, but not much else. The kids are learning about native plants, pollinators, and water harvesting. They have recently expressed interest in planting a vegetable garden. They would like to donate the produce to the local food bank. I think this is a great idea!
In addition to the garden, we are building bat houses, bird houses, and hummingbird feeders. It is a huge undertaking, but the kids are so into it. And it is something the entire school, and our community, can benefit from.
If anyone has advice, stories, hints, or tidbits they would like to share, I would love to hear what you have to say. I am particularly interested in the water barrel idea.