Accurately estimate how much of an amendment you need!
Mulch, loam, compost, etc. in bulk is usually sold by the cubic yard or in bags by the cubic foot. If you need less than a 2-3 cubic yards of material buying in bags by the cubic foot is probably your best option. For amounts over a yard buying in bulk is typically your cheapest option. Bear in mind, that if you are having bulk materials delivered there can be a minimum or a threshold amount required for delivery (for example 3 yards). This will vary by supplier so you should be prepared to call around if you only needone1 or two yards of material delivered.
To determine how much material is needed you must know the square footage of the area receiving the materials and how many inches thick the layer of material should be.
Once you know how thick of a layer you need to apply, calculate the square footage of your site. If your area is a square or rectangle, simply multiply the length times the width of the plot. If your site isn’t square (such as a large curved bed) break it up into a series of adjoining squares until you have a good approximation of the square footage.
To calculate cubic feet: Multiply your square footage by the thickness of your added material measured in feet (1 inch = .083 feet). This figure will give you the cubic footage you need.
To calculate cubic yards: To convert this to cubic yards, divide your cubic footage by 27.
For example, a 12’x 12’ needs a 3” thick application of loam.
- Multiply 12’x 12’ to get 144 sq. ft.
- Convert 3” to feet by dividing by 12 = .25’
- 144 sq. ft. x .25 feet = 36 cubic feet
- 36 cubic feet divided by 27 = 1.3 cubic yards.