How to Transform a Slope Into a Terraced Garden

April 30, 2021 by

Collaborative Post

The small backyard plot of my former property first appeared as nothing more than a patch of ground leading up to a steep slope, a little hill that seemed impossible to landscape. I addressed the challenge by creating a terrace garden—a series of smaller gardens that divided the sloped area into smaller, level, tiered sections. The terrace garden also prevented erosion by more easily distributing the water so it could be better absorbed into the ground.

Lynn Greyling, Public Domain Pictures.

As for any garden, you’ll want to settle on a design that suits the slope, function and look you envision for the garden.

Here’s a basic guide to creating a terraced garden.

Measuring the garden.
Before you start digging, measure to figure out how many tiers you’ll need. The easiest method is to measure the rise of the garden and its run. The rise is the height of your garden’s slope, the vertical distance from the bottom to the top. The run is essentially the length of your garden’s slope.  So, if you have a garden with a 10 foot rise and 20 foot run, and you want each terrace to have a 2 foot drop, you’ll need to cut five tiers.

Planning the Garden
Your design may not call for evenly sized tiers, especially if you’re planting different things on each level, such as vegetables, shrubs or alpines. You may also encounter some obstacles, like trees, that will require a workaround. Start with a solid planting scheme to lay out what to plant on each level. Bear in mind too that plants with good root systems could help strengthen the tiers. After planning the tiers, it’s time to determine the type and quantity of materials you will need.

Choosing Materials
To hold the tiers in place, you’ll need to create retaining walls. As they are easy to work with, pressure treated wood or landscaping timbers are the most commonly used materials, but the walls can also be made from other materials such as stone or brick. If you plan to plant vegetables, use cedar wood to avoid chemicals leaching into the soil.

For my terraced sections, we created the tiers from short dry-stacked walls (no mortar) of locally sourced granite rocks, plentiful in the New England area where my garden was located. The foliage eventually overflowed from some of the back tiers to ones in front. If you’re hiring a professional, don’t forget to budget for the cost of building a wall for each level, including materials and labor.

Natalia Otero, Wikimedia Commons.

Creating the Tiers
Begin by marking the ground to ready it for digging trenches for the tiers. This part of the project is going require the most physical effort, so you may need some professional help, or at least some strong arms. If you’re using wood, drive posts into the ground and screw the lengths of wood to them to create sturdy walls. The general rule for posts is they should be as deep as they are high.

Start from the bottom of the slope and work your way up, digging the ground out from the back of your tier and moving the soil to the front to create a level. Make sure the bottom trench stays level with the first trench. If your soil is dry, then water it before you start as this will make it easier to work with.

Planting the Terraces
Let the fun begin! Here’s where you return to your original plan and vision for the garden. Begin looking for plants suitable for your particular location’s climate, soil and light conditions.

You may choose a variety of plants and flowers, or decide to mix them up with vegetables and herbs. Whatever your choice, properly research what each plant needs to thrive. In some drier planting zones, a xeriscaped terrace garden of water-wise succulents can be a smart low maintenance and beautiful choice. In my terraced garden, I mixed up tall ornamental grasses with a variety of perennials including lilies and bigleaf hydrangeas.

Under my Connecticut covered patio with terraced garden in background. Robin Plaskoff Horton, Urban Gardens.

Whatever you plant, allow yourself to sit back and enjoy your transformed little hill.

Unless otherwise notes, all images by Robin Plaskoff Horton for Urban Gardens.












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