Combating Soil Erosion in the Garden

A series of retaining walls under construction hold back the earth of a terraced garden.
What You'll Need
What You'll Need

Slopes, hills and valleys provide wonderful visual interest for landscapes, but they can be difficult areas to garden. Often, heavy rains wash soil nutrients away including topsoil, making growing anything but the hardiest plants extremely difficult. Here are some simple methods to combat the erosion problem in various settings.

Slight Slopes

Planting hardy groundcover is an excellent way to control erosion problems on slight slopes. Purple wintercreeper is an attractive evergreen groundcover that thrives in full sun or full shade and spreads quickly to form a bushy mat. Low growing junipers require very little care and will grow in poor soil. Herbs such as oregano and thyme are easy to grow as groundcover, and add fragrance and beauty to the landscape. If you have a larger area to cover, there are many ornamental grasses that make excellent groundcover and help reduce erosion significantly.

Moderate Slopes

Retaining cloth can be used if the erosion is more severe. Usually made of burlap, this cloth is only to be used on slight hills because it will prevent rainwater from penetrating into the soil. In fact, before a retaining cloth is installed, be sure to give the ground beneath a heavy soaking with the garden hose. Other solutions include placing mulch or stone riprap.
TIP: Our expert gardening advisor, Susan Patterson adds, "Mulch, which soaks up rainwater, can be used alone on a slight slope, but stone riprap is an excellent soil preserver that also works well on steep slopes. Stone riprap works like a small retaining wall and will certainly prevent soil erosion on slight hills and slopes."

Steep Slopes

When slopes become slightly steeper, you may need to step up your plans to keep soil in its place. Building contours and bevels are excellent solutions for tougher erosion areas. Contours are excellent for climates with heavy rain because they intercept the flow of rainfall and steer it to any area the gardener or landscaper wants it. Flexible plastic drainpipe is most often used for this purpose and may be found at your local home improvement center. Of course, you do not want your pipeline to fill up with silt and debris, so this must be laid at a sloping angle in order for such materials to be flushed downward.

Bevels require some basic carpentry skill if you plan to install them yourself. Bevels are essentially boxes without a bottom installed horizontally down your slope and filled with soil. These are excellent for annuals with shallow roots and will transform your plain slope into a showy garden of blooms if you so choose. Since roots will be above the ground level, be sure to use plants with shallow root systems.

Finally, erosion on a steep slope may be conquered with retaining walls, terraces or ground cover that thrives in poor soil conditions. Generally, for most slopes a retaining wall 3 feet high will be adequate and attractive. Several such walls built along the slope constitute a terracing effect which is both attractive and convenient to garden. Terraces, more than any other method, reshape your difficult slope into what may be the focal point of the landscape. Terraced gardens may be constructed with stone or even railroad ties.
TIP: Susan suggests, "If your slope is very steep consider hiring a professional to landscape."

Click here to purchase gardening supplies.