How Deep Should Rock Be Used for Landscaping?

Using rock for landscaping is both aesthetically pleasing and functional. But how deep should the rock be used for landscaping applications? As rocklayers, the amount of depth needed for rock depends on the desired results, location of the project, and type of material.

Underlayment

Rocks are often used as an underlayment for walkways, driveways, and flower beds. In this case, the primary goal is creating a stable base which prevents soil from shifting or settling over time. The general depth for this type of project is two inches, although some situations may require a deeper layer for stability.

Hardscape Features

When creating hardscape features such as walls or stairs, the depth of the rock can be considerably greater. The most common depth for feature walls, for example, is between 6 and 10 inches. For stairs, the depth of the rock is usually between 4 and 8 inches.

Rock Gardens

Rock gardens of the type used for xeriscaping or other decorative purposes also require a specific layer of depth. In this case, 3 to 4 inches is typically enough to provide a striking appearance without compromising the stability of the landscape.

Hedges and Borders

When rock is used to create a hedge or border, a depth of 3 to 4 inches is generally enough to create a visually appealing focal point. For larger rocks, 4 to 6 inches of depth should be sufficient.

Location

The particular location of the landscaping project can also affect the required depth of the rock. Areas that receive heavy foot traffic, for instance, may require a greater depth of rock to prevent shifting or erosion.

Material

The type of material being used for landscaping may also influence the depth of rock needed. For example, a larger rock may require a greater depth than smaller materials.

In Summary

The amount of depth needed for rock when landscaping depends on the desired result, location, and material being used. As a general rule, rock for landscaping should range between 2 and 6 inches in depth, with some applications requiring a greater depth.