A series of wide steps would break up the length of the boxes and provide entry into the garden at various places along the deck. And the low height of the planters, only 18 inches higher than the deck, would give me my view. As I made drawings, I realized that these boxes solved all the problems at once. The boxes give the deck an open feeling, and broad steps invite visitors into the garden. If you use planters to replace a railing on a deck, make sure they conform to building codes.
Situations vary, so always make sure that any substitute for a railing meets code.
I was lucky to find Dave Manning and Jody Proctor, two talented carpenters, who took my drawings and turned them into real plans. This allowed us to use the same pattern for both the boxes and the steps, simplifying the design. The problem of how to handle the runoff generated by watering the planters was solved with a simple French drain under the boxes. We laid down perforated pipe in gravel and hooked that into the existing gutter drains. Don't overlook this step because it's critical that water not undermine the deck or seep toward the house foundation.