apartment therapy changing the world, one room at a time

Think of earthquakes. Nothing should be hung outside a window.

Landless:
Having not lived in the bay area very long, how is a flowerbox a hazard in an earthquake? It's generally *below* the glass.

If you keep the material "soft", you shouldn't have too much trouble.
Have you considered using small plastic faux terra cotta pots hung with wire loops? Nothing bigger than six inches around (so it wouldn't hurt anyone if it fell or stress the window frame to much) but enough for a small herb garden or mini impatients...

In an earthquake, things fall down. A flowerbox could be dislodged from the window sill and kill a pedestrian. If you walk through the Financial District, observe how older buildings, unlike those in Chicago and NYC, lack ornamentation. Keep things flat and bolted against the wall.