They're simple, cost effective and give you a huge bang for the buck! Next, i added the legs with a bit of wood glue and nailing each in place, recessing them 3″ into the planter box. Planter Boxes Elevated Cedar Planter Box Orders 99 Using the jigsaw wood blade, measure and cut the fence board into 12 pieces, each measuring 16.25” long.Diy standing planter box plans. For the planter box sides: Adding a diy planter box to your porch or yard is a