Raised garden beds allow you to add soil within a confined area, enabling you to condition the soil in each garden bed to suit the needs of specific plants. Before building or setting up your garden beds, loosen the soil in the designated locations to encourage proper drainage. To add soil to your garden beds, you'll need to calculate the cubic foot area of the raised beds.
Calculate the amount of soil needed for each garden bed. Soil is sold by the cubic foot. You need to measure your garden beds to determine the total amount of cubic feet of soil required to fill your garden beds.
Measure the length and width of each garden bed. Measure the depth of each bed. Multiply the length and width. This result is the square footage of the bed. Multiply the square footage by the depth. The resulting figure is the cubic foot area.
For example: The length is 6 feet. The width is 4 feet. 6x4=24. The depth is 2 feet. 24x2=48. The garden bed holds 48 cubic feet of soil.
Add the total number of cubic feet calculated for each bed. This figure represents the total amount of soil needed for your garden beds.
For example, if you have four garden beds each requiring 48 cubic feet of soil, multiply 48 by 4. The final figure is 192 cubic feet.
Visit your local garden center or garden outlet of your choice. Packaged garden soils are customarily available in a variety of quantities, but are sold by the cubic foot. A small bag of garden soil may contain 3 cubic feet of soil. Purchasing in larger quantities may be more cost effective when starting new raised garden beds.
Determine how many bags of soil you need to purchase. Divide the total cubic feet of area by the amount of soil in one bag. For example, if the garden center offers bags of 10 cubic feet, divide 192 by 10. The result is 19.2. Purchase 19 bags of soil.
Fill each garden bed with the soil. Do not push down or compact the soil. Pour the soil in so it lays in a loose, fluffed fashion. Leave a gap between the surface soil and the top of the garden bed. The gap may be between 2 to 6 inches. The gap allows you to work in the soil and, if needed, add mulch around your plants.
Rake the soil surface of each bed with a rake to smooth. Install your plants. Add mulch if desired.