Planters can add dimension to your landscape and character to your outdoor living space. From old wheelbarrows to coffee cans, you can build planters out of a variety of materials. You can also build planters with landscape timbers that would normally border flower beds or brace a retaining wall. Landscape timbers are already treated for outdoor use, so it is not necessary to treat the wood. Build a standard box shaped planter or miter the cuts and vary the design to build octagonal planters.
Cut four landscape timbers in half. Cut two landscape timbers into eight 2-foot long sections. Each landscape timber measures 4 inches wide by 4 inches deep by 8 feet long. After making the cuts, you will have eight 4-foot long sections and eight 2-foot long sections to build a rectangular planter.
Stack two 4-foot long landscape timbers so that the edges are flush. Measure and mark the top timber 3, 12 and 20 inches from each end. Hammer a 6-inch long pole barn nail straight down through the top timber and 2 inches into the bottom timber at each mark.
Stack another timber on top of the first two so that the edges are flush. Measure and mark the top timber 5, 14 and 22 inches from each end. Hammer 6-inch long pole barn nails straight down through the top timber on each mark.
Stack another landscape timber on top of the first three so that the edges are flush. Measure and mark the last timber 3, 12 and 20 inches from each end. Hammer a 6-inch pole barn nail straight down into the top timber on each mark. The four connected timbers make one long side of the planter.
Repeat Steps, 2, 3 and 4 once more to make the other long side of the planter.
Stack two 2-foot long landscape timbers so that the edges are flush. Measure and mark the top timber 4 inches from each end. Join the stacked timbers with pole barn nails on each mark. Stack another 2-foot timber on top, make sure that the edges are flush and mark it 5 inches from each end. Hammer nails on the marks. Stack another 2-foot long timber on top so that the edges are flush. Mark the last timber 4 inches from each end and secure it to the first three with pole barn nails. Repeat this step to make the fourth side of the planter.
Stand one of the 4-foot long sides of the planter perpendicular to one of the 2-foot long sides. Make sure that the edges are flush to make a corner with the 2-foot long section inside the 4-foot long section.
Insert a 6-inch pole barn nails through the landscape timber on the outside of the 4-foot long section and into the timbers on the 2-foot long section. Insert one nail into the center of each stacked timber.
Repeat Steps 7 and 8 to attach the remaining two sides together. Join the two corner sections together with four pole barn nails inserted along the vertical edges.
Measure the dimensions from the outside edges across the bottom of the planter. Cut a section of 1/2-inch thick treated plywood to fit the dimensions. Attach the plywood to the base of the planter with 2-inch long deck nails placed every 3 to 4 inches.
Drill four to six 1/4-inch diameter holes into the plywood base for drainage.