Repurposing salvaged wooden shutters to make a planter box can add a unique touch to otherwise traditional-looking planter boxes. The simplest method of using shutters in the construction of a planter box is simply to nail the shutters to an existing box of similar dimensions, after sanding and repainting the shutters. If you're using functional plantation shutters, you will need to glue or nail the shutters to render them immobile; other types of shutters may require sealing with wood putty and glue if you'll be using them without a plastic liner. Shutters are commonly between 28 and 36 inches long; many plastic planter boxes come in lengths between 24 and 48 inches and will fit neatly inside a shutter planter box.
Building the Box
Cut, or have cut at the hardware store, the bottom board to your desired width; a good width is around 8 inches, as this will accommodate most standard-size plastic planter liners. Cut the end boards to the same width as the bottom board and to the desired length, depending on how wide you want your shutter planter box to be.
Sand the shutters using the coarse-grit sandpaper to remove imperfections and paint. Follow up by sanding with fine-grain sandpaper to polish the wood, and finish by wiping with a soft cloth to remove dust and grit.
Apply glue to one edge of a shutter and hold in place on the bottom board or clamp in place until the glue dries. Repeat for the other shutter.
Glue the side pieces in place in between the shutter sides and allow to dry completely.
Drill in wood screws at regular intervals on the bottom of the planter box into the shutter sides and ends to ensure a tight fit. Use wood putty to fill the screw-holes, if desired, as well as any gaps along the seams of the boards. This gives the box a more polished appearance once it is painted and also aids in keeping moisture out.
Drill a series of drain holes in the bottom board to allow water to drain out. Drilling two or three holes near the edges and in the center of the planter should provide adequate drainage.
Prepare the planter for painting by applying a layer of paint primer. Allow the primer to dry completely before painting.
Apply two or three layers of paint to the entire box, inside and out, including the bottom of the box. If you like the raw-wood look, apply a layer of polyurethane or other waterproof sealant. Allow paint or sealant to dry completely between each application.