Because these beds are sitting above the ground it permits the air to circulate around the containers and allows the sun to warm them up quicker. This will allot for earlier planting and quicker germination especially in the colder climate areas.
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.
Some of the other benefits of raised beds are: reachable - less bending and stretching gives the gardener easy access and makes maintaining and harvesting less of a task to perform; drainage - because the soil is above the ground it will not become compacted during heavy rains and will drain properly in preventing water-soaked soil;
Numbering starts in the upper left corner and moves left to right, top to bottom. For example, planting square A1 is the upper left-hand square (1st column, 1st row), while planting square C4 is the square in the 3rd column and the 4th row. I have yet to find a commercially available garden bed with an included feature for marking off planting squares.