Fluctuating temperatures that lead to freezing and thawing can turn your garden's neat edging into a crooked mess. Pavers tilt, raised beds bow and borders drift out of place. The culprit is a natural but powerful process called frost heave.

Understanding how it works and how to prevent it will help your landscape edging stay put season after season.

What Is Frost Heave and Why Does It Move Your Garden?

You might recall from high school geology how a small amount of water can break apart a large rock through mechanical erosion. The same happens to soil when the moisture in the ground freezes and expands. Because ice has about 9% more volume than water, it pushes against the surrounding land as the moisture freezes. This filling-out process pushes upward against fence posts, lifts pavers and raises beds.

When the ice melts, your garden beds settle unevenly, which is why you’ll notice gaps, cracks, and leaning perimeter or retaining walls. The type of dirt influences the amount of frost that forms. Clay and silt substrates hold more water, which results in greater movement. Because water moves down into the garden bed, it expands nearer the bottom of your raised frames, causing these to bulge outward and pop or split.

Come spring, your beds need releveling, and once-neat paved pathways are out of alignment. Fence posts aren’t safe, either. You may find a loose garden gate if the soil erodes around the base due to the freeze-thaw cycle, which causes the dirt to move away. Fences, posts and wood bed frames can crack as a result of extreme temperature changes, weakening your overall garden infrastructure. Inspect and intervene regularly to maintain your yard.

How to Prevent Shifting With a Correct Foundation

A stable garden starts below the surface. Whether you’re installing new pavers, edging or raised beds, a strong foundation is your best defense against frost heave.

Dig a Proper Trench

Dig a trench of about 4-6 inches deep along the area where you’ll place your edging or paving. This gets your base below the most active frost zone, minimizing upward pressure. Remove loose soil and compact the base before adding your chosen materials. Do the same beneath your raised bed frame.

Build a Strong Drainage Base

Next, add 4 inches of crushed gravel and stamp it down firmly to improve stability and drainage. Follow this with an inch of coarse sand to create a smooth, level base. The gravel keeps water from pooling under your unit, while sand locks everything in place and reduces the chances of frost-related movement.

Why Material Choices Matter for the Border

Your choice of edging material significantly affects how well your garden withstands winter conditions.

Concrete Pavers

Concrete slabs are a durable landscaping choice when installed correctly, accompanied by a nonwoven landscape fabric that allows water to drain, preventing waterlogging. They require a well-compacted base for appropriate drainage. If ice penetrates deeper than the 6-inch subbase, it can still cause the earth to lift and move. You can sweep polymeric paver sand between joints to help lock them together and prevent water from entering.

Metal Landscape Edging

Metal is less likely to move than concrete or plastic, making it a durable choice. Steel perimeters are ideal for clean, defined borders. Steel or aluminum holds its shape through temperature changes. Install a metal border at a depth of 3 inches and secure it with steel stakes to ensure long-term stability.

Wood for a Raised Bed

Wooden bed frames are ideal for raising vegetables to prevent grass from creeping in, and they’re a sustainable option. However, they need reinforcement against warping and soil pressure. Untreated cedar or redwood are among the best wood for raised garden beds, but you should add proper bracing and drainage.

When Raised Beds and Fences Need Protection

The same forces that shift pavers can wreak havoc on wood structures. As frozen earth expands, it presses against raised bed walls and fence posts. Over time, repeated cycles can cause corners to separate or posts to lean.

A leaning fence is often caused by post issues, either from rotting wood or unstable footings. A wooden post may need to be replaced entirely if there’s significant rot at the base. Check for loose or rusted screws, nails and brackets, especially after a season of harsh weather.

Aftercare for posts includes backfilling with soil and gravel to eliminate seepage gaps. Do the same with pavers by adding polymeric sand to the cross-spaces and misting it lightly to harden into a protective seal.

Minimize frost damage for raised beds by adding heavy-duty landscape fabric and cross-braces along the long sides to prevent bowing. Ensure drainage by lining the base with coarse gravel. Reinforce corners with galvanized brackets for added strength.

Why Nature’s Secret Weapon Is Plants

Adding organic mulch helps keep the soil warm in winter and cool in summer, while retaining moisture during the dry season. However, plant roots are the real heroes. Like mycelium, these bind the earth. Fine hairs weave particles together, reducing the risk of separation, erosion and ground movement during freeze–thaw cycles.

Perennial borders moderate soil temperature. Low, hardy plants such as creeping thyme or ornamental grasses help regulate moisture and insulate the earth. Deep-rooted companions improve drainage. Crops like comfrey and carrots loosen compacted dirt and encourage water to move away from sensitive areas.

Winter cover crops protect bare land. Clover, rye and vetch add structure and organic matter, helping maintain a consistent substrate profile even through winter. By combining living roots with smart edging, drainage and material choices, you create a garden that works with nature’s cycles instead of against them.

What Can Prevent Frost Heave?

Winter’s freeze–thaw cycles can be tough on any garden, but your smart prep keeps everything in place. A strong base, good drainage, durable materials and a few living helpers, like roots and cover crops, go a long way toward preventing frost heave. With the proper foundation, your pavers, fences and raised beds will stay level, secure and ready to welcome spring.