Last week, when I volunteered at the SF Victory Garden, I was intrigued by the rice straw wattles that were used to form the garden beds. Rice straw wattles are essentially rice straw, an agricultural bi-product that is enclosed in a netted tube. Both lightweight and malleable, rice straw wattles are often used for erosion control in landscaping, but also work well for garden beds.
I definitely think rice straw wattles are a good option for first-time gardeners who aren't that handy with woodworking tools. By simply connecting a few wattles together, you can create a garden space in a fraction of the time it would take to build a garden box. They also would work well in a space, such as a rooftop garden, where weight is a consideration. I also love the organic, circular shapes that are easily created with wattles.
If you're interested in trying these for your garden, check out Earth Savers' wattles.