Urban gardening is now very popular these days because of food safety awareness, our financial economy, and because we want to be eco-friendly. Just because you only have a garden area that is very small does not mean you cannot use some small raised garden beds on a patio, deck, or back porch for some herbs, vegetables, flowers, or ornamental plants to enjoy.
Spacing for anchors: Usable Length (in inches) / Total Length (in inches) * 12 inches. For my beds, I calculated a spacing of 11.75 inches for my 8 foot board by dividing the Usable Length of 94 inches by the Total Length of 96 inches and multiplying this by 12. My four foot boards require a spacing of 11.56 inches.
Lastly, connect your anchors using a heavy-duty string or twine, creating a grid-like pattern of planting squares. You can see an example of the results of this process in my garden bed here: Square Foot Planting Squares.
Number of anchors per board: (Usable Length / Spacing for anchors) - 1. For my beds, I need 7 separators for each 8 foot board and 3 for each 4 foot board.