Using a raised bed will lengthen the amount of growing time for most vegetable plants. Typically plants can be placed in the raised bed earlier in the season and grown to a later date if a clear plastic cover, like a small greenhouse, is installed over the bed area. Once the raised bed is made, you will have to fill it with quality topsoil. Using a tape measure and pencil and paper or a calculator you can measure the bed, calculate the cubic feet, and then order the topsoil.
Measure the overall interior length of the raised bed. A typical raised bed may have an interior length measurement of 8 feet.
Find the overall interior width of the growing bed. A typical width measurement is 4 feet.
Calculate the square footage of the raised bed by multiplying the length, 8 feet, times the width, 4 feet. The result is 32 square feet.
Measure the interior depth of the raised bed. This measurement should be from the top level on the sides of the raised bed, down to the ground on the inside. The depth of the bed may be 1 1/2 feet.
Find the total cubic footage of the raised bed by multiplying the area, 32 square feet, times the depth, 1 1/2 feet, or 1.5 feet.
32 times 1.5 is 48. The cubic footage is 48 cubic feet.