- 1). Place a pair of ¾-inch plywood boards with a length of 48 inches on a worktable. Measure 12 inches across the width of the board with a tape measure and make a mark. Repeat this step with the other plywood board. Cut the boards along these marks using a circular saw. These 2 boards with form the sides of your planter box.
- 2). Place 2 more ¾-inch plywood boards on a worktable. Measure 12 inches across the width of the boards, mark the measurement and cut the boards with the circular saw so that the 2 boards equal the height of the side pieces. Determine the desired length of the 2 boards. Make the appropriate marks on the boards and cut them to size with the saw.
- 3). Butt the end of 1 longer side board against the end of a shorter board. Hammer in a set of galvanized nails to secure the 2 ends together. Repeat this on all 4 sides of the rectangle to form the frame of the planter box.
- 4). Measure the full length the planter box. Mark the measurement on a ¾-inch piece of plywood with a length of 48 inches. Cut the plywood with the circular saw. This piece will form the bottom of the planter box. Place the wood piece on top of the frame. Use a hammer to drive a galvanized nail through each corner of the bottom piece to secure it to the planter-box frame.
- 5). Turn the planter box over. Using a drill and a ½-inch drill bit, drill holes in the plywood. Space each hole apart by 6 inches for water drainage.
- 6). Use the side of a putty knife to spread a layer of roofing cement, according to the manufacturer's instructions, along the interior wood surface of the planter box. The roofing cement will create an airtight layer and prevent water from rotting the wood.
- 7). Using scissors, cut a length of landscape fabric to fit the base of the planter box. Place the landscape fabric on the bottom of the planter box. Pour potting soil into the planter, and plant the desired plants or flowers in the planter.
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