The wall gardening idea takes a new direction...with coffee cans!
Find out how to do this -- and other ideas with cans -- at Re-Nest.
A whole batch of creative re-use ideas for other items here, too.
My only worry: it gets so hot here in full sun that I'm afraid the plants would literally boil in place. But for the price of a little paint, a hook and a nail or two, it's sure worth trying.