As temperatures fluctuate in late fall and the winter season, the freeze-thaw cycles cause soil to expand (heave) and contract. This can force plants, roots, and even hardscaping elements upward. Left unchecked, this natural phenomenon can be a challenge for homeowners. It can lead to damaged plants, uneven surfaces, and a host of frustrations come springtime. But with a little preparation and care, there are things you can do to protect yourself and your property from the effects of frost heave.
What Causes Frost Heave?
To understand how to combat frost heaving, it’s helpful to know what causes it. In cold climates, when water in the ground freezes, it expands. In areas with poor drainage or compacted soil, this expansion of water has nowhere to go but up, lifting the ground, plants, and even structures or concrete slabs. As soil temperatures warm, the ice melts and the ground settles—sometimes unevenly. This repeated cycle of freezing can disturb plant roots, expose bulbs, shift pavers, or even cause structural damage, depending on frost depth.
Areas with clay-heavy soil types have a greater risk of frost heave during these periods of freezing since this type of soil holds more water. Additionally, newly planted gardens or lawns may face more disruption because roots and bulbs haven’t yet had time to establish themselves under the soil surface.
Prevention of Frost Heave
Protecting your lawn and garden doesn’t require an overhaul of your outdoor spaces. Simple preventative measures can make a significant difference in lowering your risk factor:
- Amend your soil: Loosen compacted soil by mixing in organic matter like compost or a blend of sand. This improves drainage and reduces water retention.
- Mulch generously: Add a thick layer (2-4 inches) of bark mulch or organic mulch around plants and over vulnerable areas. Mulch acts as a layer of insulation, keeping soil temperatures more stable and reducing freeze-thaw cycles. Shredded leaves can also provide a blanket of insulation.
- Choose deep-rooted plants: Perennials with deep roots are less likely to be dislodged by frost heave. Native plants adapted to your region’s conditions are especially resilient.
- Water deeply before the ground freezes: Well-hydrated soil is less prone to frost heave because it doesn’t freeze as quickly.
- Avoid late-season fertilization: Fertilizing late in the season encourages new growth. It's great for your lawn, but leaves landscaping plants more vulnerable to frost damage.
- Layer rocks and sand beneath hardscaping: For hardscaping elements like walkways and patios, proper installation with a gravel or sand base helps maintain stability.
Caring for Your Garden in the Spring
If frost heaving does occur, don’t panic. Quick action in early spring can help reduce its damaging effects. Check for exposed roots or bulbs and press them back into place. Reapply mulch to areas where it may have shifted, and water plants to encourage re-rooting. If hardscaping elements have shifted, plan to reset them once the ground has settled and dried out.
How do I know if my soil is prone to frost heave?
Types of soil with high water content, like clay soil or silty soil, are more likely to experience detrimental effects of frost heave. If you notice wet soil or pooling of water in your yard after rain or uneven settling in your garden, these are signs of excess soil moisture and you may be at risk.
Can I completely eliminate frost heave in my garden?
While you can’t control air temperature or stop the forces of nature, you can minimize frost penetration during winter months by improving soil drainage, mulching effectively, and choosing plants that are well-suited to colder climates. Consistent care and attention to soil health go a long way in reducing its impact.
