Spiral Gardens are the new hot idea for small space gardening. You can tuck one of these small gardens into the most unlikely tiny spaces. This technique is particularly suited for growing Herbs. Nothing tastes better than fresh Dill or Basil.
You can use all sorts of things to make the spiral from the grand to the mundane. Use bottles, bricks from an old building, river stones. You will get lots of building instructions and information at The Micro Gardener. As is usual for me, I just winged it when I made my spiral garden. Turned out just fine.
These gardens are particularly suited to Herbs. Choose one tall imposing plant like Zucchini for the center. Trust me, no family needs more than one Zucchini. Or maybe one lovely Okra. Do not forget that elevated beds need extra watering to do well.