I wanted to dress up my porch railing, but rather than build flower boxes out of wood, I took a shortcut and used plastic rain gutters.
I cut them about 3 feet long, slipped on the mounting brackets and end caps, and drilled 1/4-inch holes in the bottom for drainage. Then I fastened them directly to the railing with a couple of decking screws.
I lined the bottom with landscaping fabric before adding soil and flowering plants.
Watch the video for details.