So, what is a planting board? A planting board is a 1 x 4 board that is four feet long. Relatively
deep notches are cut every foot with shallow notches at 6 inches from each deep notch. Some
gardeners also bevel the side opposite the notches so they can work the beveled end into the soil
to make a shallow trench for seed.
When planting, lay the planting board near your tent peg and align it with the string. It is now
easy to place plants or seeds at the recommended spacing. Move the planting board with you as
you progress down the row. (Ward Upham)