Frost heave can damage your outdoor plant box during winter, but with the right strategies, you can protect it effectively. Here’s how to make your plant box more frost-heave resistant:

1. Choose the Right Material: Opt for durable, frost-resistant materials like cedar, redwood, or composite lumber. These materials withstand temperature fluctuations better than others.

2. Elevate the Plant Box: Place your plant box on bricks or feet to allow proper drainage and prevent water from pooling underneath, which can freeze and cause heaving.

3. Insulate the Soil: Add a layer of mulch or straw to insulate the soil. This helps maintain a consistent temperature and reduces frost penetration.

4. Use a Frost Blanket: Cover the plant box with a frost blanket or burlap during extreme cold spells to shield it from freezing temperatures.

5. Proper Drainage: Ensure your plant box has adequate drainage holes to prevent water accumulation, which can lead to frost heave.

By implementing these measures, your outdoor plant box will be better equipped to handle winter conditions and remain frost-heave resistant. Happy gardening!