2. cedar 1¼×6s Get four 6-foot boards to make the 63-inch-long seat, and one 8-foot board to trim the tall planter.
3. ¾-inch gravel for drainage below the planters and to fill the assembled planters. Get at least 1½ cubic feet (three bags).
4. potting soil to top off the planters filled with gravel. Get four 32-quart bags.