As for building a timber-framed bed, no carpentry job could be easier. Simply join the corners together with galvanized nails or screws. I used 1 ½-inch nails for my thin pine-framed beds, and 4-inch screws for my thicker hemlock models. Although corner posts are commonly used for raised beds, I have not found them necessary.
Before filling a frame with soil, it is imperative to line the bottom of the bed with either corrugated cardboard or several thicknesses of newspaper. This material will smother any weeds or grass that would otherwise grow up through the raised bed and that would impede your perfect planting plan.