Good idea if you have rock solid ground that is hard to dig up. If you don't cover the holes you can use them for herbs & annuals. also lined with weed barrier cloth & used rebar in several places for stability. It makes maintenence super easy.
Love this idea. Build seating around edge of deck with planter boxes behind. Built-in planter boxes and landscape ideas. Gorgeous planter box ideas with built-in garden boxes. Lots of fun ideas, projects and tutorials.