The close plant spacing and the use of compost generally result in higher yields with raised beds in comparison to conventional row gardening. Waist-high raised beds enable the elderly and physically disabled to grow vegetables without having to bend over to tend them.
Then, determine what you would like to use for the anchors. If you built your garden bed out of lumber, you could use nails as anchors, spacing each nail the appropriate distance as determined by the results of the calculation in Step 1 above. If your garden bed is made out of a composite material (part wood waste, part plastic), I recommend using an anchor placed on the outside of the bed. Since my beds are 6 inches high, I used 12 inch metal spikes I bought from the local hardware store, pounding them into the soil directly on the outside of the garden bed.
The 4x8 foot garden beds I bought, for instance, are 4x8 feet from end to end. But when you connect the boards at the corners, you lose a few inches, so the interior dimensions of the garden bed are actually a few inches short of the advertised size. In my case, my beds have an interior dimension of 46.25 inches x 94 inches. I refer to these dimensions as Usable Length for the remainder of this article.
A 4x4 foot garden bed, for example, will have 16 planting squares (because there are 16 square feet in a 4x4 bed). A 4x8 foot garden bed will have 32 planting squares.