People who have small decks, patios or balconies often feel left out but not anymore! Check out this guide to using pallets as a vertical garden. I can't see any reason that vegetables won't work in this, things like lettuce or even strawberries. You could have a vegetable/fruit/flower mix. And pallets are pretty much free, aren't they? :)
ETA: Pallets are often treated with chemicals so to grow food one should make a pallet out of untreated wood.
