Adding topsoil to a garden bed raises its level and creates a layer of rich growing soil. Before purchasing a load of topsoil, you should determine how much you will need. Determine the area of the location where you'll be placing the dirt and calculate its volume in yards. When you go to purchase topsoil, typically sold in yards, the measurements from your calculations will match the topsoil's unit of measure.
Things You'll Need
- Measuring tape
Measure the length and the width of square or rectangular garden areas. Multiply the two numbers together to get the area.
Find the area of triangular gardens by measuring the length of the bottom leg of the garden bed, then the height of the bed. Multiply these two numbers together, and divide by 2.
Determine the area of a circular garden by measuring from the center of the bed to one edge. This measurement is the radius. Multiply the radius by itself, then multiply that number by 3.14, or pi.
Calculate the volume of the garden bed. Decide how deep you want the topsoil layer to be. Multiply this number by the area of your garden bed. This number, in cubic yards, is the amount of topsoil you need to cover your garden bed.
Tips & Warnings
- Area measurements are in square units: square yards, inches or feet. Once you determine the volume by multiplying the area by the depth, you are working in cubic units.
- In small spaces, measuring in feet or inches may be more convenient; just remember to convert the measurement to yards before you order the topsoil.
- Photo Credit preparing soil for garden image by Cherry-Merry from Fotolia.com
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