The pebbles clearly demarcated the growing strips. Water drained out of pots flow right under the pebbles, keeping the feet and the paws out of the dirt. Thus, the balcony-garden are free to roam again :)
This balcony-garden started at the beginning of 2008. Took a few months to settle into the first completed look in this photo (last Oct), which I liked very much for its dreamy feel sans the congestion (which was a problem this year until The Slimming Plan was written).