Raised Bed Construction - Raised Bed Gardening - page 88

Table 4 shows the nominal and actual dimensions of common dimensional lumber. The
Maximum Slope that lumber of each size can level is the actual width of that lumber. 2x4
lumber can only level a slope of 3½ inches and 2x12 lumber can level a slope 11¼ inches.
2x4s would really be more of a border than a raised bed, but you get the idea. Also, con-
sider that two 2x12s stacked on top of each other could level an area that had a slope up to
22½ inches.