A hydroponic garden is a great option if you have limited space or live somewhere you can't plant a traditional garden. This PVC-based hydroponic garden hangs over a wall or fence, making it a great choice when you can't use a more permanent solution.
This build comes from Instructables user BackyardCreations. It uses PVC gutters for the grow trays and 50mm PVC piping for the structure and irrigation system. The build is somewhat complicated, but the instructions are clear and the only tools you'll need to know how to use are a drill and a hand saw. Check out the source link for the full instructions.
Clip-on Hydroponic Wall Garden [Instructables]