I was visiting Haifa, Israel recently and saw a very interesting balcony garden. A man had run two lengths of industrial gutter (semi-circular about 6 inches wide and 3 inches deep) on the metal railing of his balcony. The gutter on the outside contained tomatoes spaced about 18 inches apart. They were full enough that I could only ID one pepper plant on the inside of the rail. He had attached some reinforcing mesh to the metal posts of the balcony for the plants to climb on, and had run a drip system through the holes of the mesh.

It was very clever and he was having much better luck with his tomatoes than I did with either my plants in ground or in pots. I think he was concerned with me making off with a tomato or two while standing there admiring his work. Unfortunately, I didn't have a camera with me at the time to snap a shot or two. I'll see if I can direct my brother back to it to take some shots.

~james