When planning a gardening or landscaping project that requires significant material, purchasing compost, soil, or mulch in bulk is often the most economical choice. Suppliers of these loose materials use a standard measurement unit, which they commonly refer to simply as “a yard.” Understanding what this unit represents is the first step in accurately estimating the volume needed. Knowing the size of a yard ensures customers order the correct quantity, preventing shortages and costly over-purchasing.
Defining the Cubic Yard
The term “yard” is shorthand for a cubic yard, the official unit of volume measurement used in the bulk material industry. It is a volume defined by the space occupied by a cube that measures three feet in width, length, and height.
Mathematically, the volume is calculated by multiplying these three dimensions: 3 feet x 3 feet x 3 feet. This results in a total volume of 27 cubic feet of material.
The use of the cubic yard ensures that whether the material is light compost or dense topsoil, the customer receives the exact same, measurable volume. This standardization is useful because the weight and moisture content of organic materials can fluctuate significantly, but the volume remains constant.
Visualizing the Volume
Translating the abstract figure of 27 cubic feet into a tangible size requires a physical reference point. One common way to visualize the volume is to consider a standard household appliance, such as a full-sized refrigerator, which is roughly equivalent to less than one-third of a cubic yard. Therefore, one cubic yard of compost is equivalent to the volume of approximately three large refrigerators stacked together.
For gardeners, the volume can be conceptualized in terms of tools; a typical wheelbarrow holds about three cubic feet of material. This means that a single cubic yard of compost requires nine full, level wheelbarrow loads to move the material to the project area.
When delivered, a cubic yard of material generally forms a significant pile on a driveway or tarp. If delivered by a small pickup truck, a single cubic yard of compost will typically fill the entire bed of the vehicle level with the cab rails.
Calculating Coverage Area
The practical application of knowing the cubic yard’s volume is determining how much area it will cover at a desired depth. To calculate the necessary volume, use this formula: Length (in feet) multiplied by Width (in feet) multiplied by the Desired Depth (in feet). The resulting total cubic footage must then be divided by 27, the number of cubic feet contained within one cubic yard.
The most common mistake in this calculation is failing to convert the desired depth from inches to feet before multiplying. For instance, a desired depth of 2 inches must first be converted to feet by dividing 2 by 12, resulting in a depth of approximately 0.167 feet. Using consistent units is necessary for an accurate result.
One cubic yard of compost provides substantial coverage for common gardening tasks. If spreading compost at a light top-dressing depth of one inch, one yard will cover an area of approximately 324 square feet, demonstrating the material’s efficiency as a soil amendment.
For projects requiring a thicker layer, such as amending poor soil structure or improving drainage, a two-inch depth is often recommended. At this depth, a single cubic yard will cover roughly 162 square feet.
When using compost as a deep mulch layer to retain soil moisture and suppress weeds, three inches thick, the coverage drops to about 108 square feet per yard. Knowing these coverage rates is important for accurately planning and ordering the correct number of cubic yards.