Economical in price, lightweight, and rot resistant, cedar or redwood fence boards are readily available at home improvement stores and are a great choice for your box project. Cedar and redwood are soft woods and are easy to work with, although they can split when clamping, nailing, or screwing. We’ll address this in the instructions. Most fence boards are sold “green,” or wet, and should be dried before using. As wood dries, especially cedar, it will move, warp, straighten, or even split until it loses its moisture and becomes more stable. To dry the wood, set it indoors or outdoors in a sunny location. It will take roughly two to four weeks for a fence board to dry, depending upon how wet it is when purchased. The easiest way to tell if boards are dry is by their weight. A fence board can be double its dry weight when it’s wet, so we recommend picking out the lighter boards in the pile.
Most fence boards come in standard 6-foot lengths and varying widths of 3½, 5½ and 7½ inches. The boards you choose will determine the height, depth and width of the box while length is fully customizable to 70 inches. Redwood fence boards are normally rough-cut to a thickness between 5/8 inch and ¾ inch, while cedar fence boards are sold at just over ½ inch thick. Fence boards will look quite rough but can be sanded down before or after building the window box, revealing their beautiful natural wood grain. If choosing a material other than fence boards, heavy sanding and drying will not be required.