When planning a landscape project, understanding material volume is the first step toward a successful outcome. The term “bark” in this context refers to a common organic landscaping material, often called mulch, which is used to cover soil in garden beds. This material is typically sold in bulk by the cubic yard, a measurement of volume equivalent to a cube measuring three feet long, three feet wide, and three feet high, totaling 27 cubic feet. Determining how much area a single cubic yard covers is not a fixed number but depends entirely on the depth at which the material is applied. This guide provides the calculations and practical advice necessary to accurately estimate your needs and prepare your landscape for installation.
Standard Coverage Rates for One Cubic Yard
One cubic yard of bark, when spread out, will cover 324 square feet of area at a uniform depth of one inch. This figure of 324 square feet at a one-inch depth is the mathematical constant used to determine coverage at any other depth. As the application depth increases, the total square footage a single yard can cover decreases proportionally. For example, a two-inch layer of bark will cover exactly half the area, or 162 square feet, from that same cubic yard.
The depth of the material significantly affects its function in the landscape. For most applications, such as suppressing weeds and conserving soil moisture, a depth of three inches is widely recommended. At this optimal thickness, one cubic yard of bark will cover an area of approximately 108 square feet. If a thicker layer is necessary for particularly stubborn weeds or slopes, a four-inch application will reduce the coverage to about 81 square feet per yard.
| Depth (Inches) | Coverage (Square Feet) |
| :—: | :—: |
| 2 | 162 |
| 3 | 108 |
| 4 | 81 |
This relationship between depth and coverage is derived from the conversion of a cubic yard’s volume into square footage at a fractional depth. Calculating the exact coverage ensures you purchase the correct amount, preventing both over-ordering and the inconvenience of running short during the project. The coverage rate is the foundation for calculating all total project needs.
How Material Type Influences Coverage
The physical composition of the material, specifically the size and shape of the bark pieces, affects the final coverage rate. Bark material is not uniform and can range from finely shredded fibers to large nuggets. Finely shredded materials tend to compact more easily and settle densely, which may result in a slightly reduced area coverage compared to theoretical calculations. Conversely, large bark nuggets create more air pockets when spread, meaning the material may initially cover a slightly larger area. The benefit of the larger pieces is that they decompose at a slower rate, offering a longer-lasting layer of coverage before needing to be refreshed.
Calculating Your Total Project Needs
Determining the total volume of bark required for a landscape project begins with accurate measurement of the area to be covered. The first step involves measuring the length and width of the garden beds in feet and multiplying these figures to calculate the total square footage. For irregularly shaped beds, it is often simplest to break the area down into smaller, manageable sections, calculating the square footage for each.
Once the total square footage is established, the desired application depth must be determined, which is typically between two and four inches. To convert the required area and depth into cubic yards, the following formula is used: multiply the total square footage by the desired depth in inches, and then divide the result by the constant 324. This calculation provides the precise number of cubic yards needed.
For example, if a flower bed measures 150 square feet and the goal is a three-inch layer, the calculation is 150 multiplied by 3, divided by 324, which equals 1.39 cubic yards. It is practical to round this number up to the nearest half or whole yard, such as 1.5 cubic yards, when placing an order. Rounding up accounts for material settling, uneven application, and minor waste, ensuring enough material is available to complete the project.
Preparing the Area for Bark Installation
Before the new bark is installed, proper preparation of the area ensures the material performs its function effectively and lasts longer. It is necessary to remove all existing weeds, debris, and matted layers of old mulch, ensuring the new material rests directly on the soil surface. Weeds, especially those with deep root systems, should be pulled completely to prevent them from growing through the new layer of bark.
Establishing a clean, defined border around the garden bed is also an important step. Using a flat shovel or edging tool to cut a clear line between the soil and the lawn helps hold the material in place and provides a neat appearance. This simple edging prevents the bark from migrating out of the bed and mixing with the turf during rain or watering. When applying the bark, it is important to maintain a consistent depth across the entire area and to avoid piling the material directly against the base of trees or shrub stems. Keeping the bark a few inches away from plant crowns prevents moisture buildup that can lead to rot and allows for proper air circulation.