Growing carrots in an outdoor plant box requires careful attention to soil depth to ensure healthy root development and a successful harvest. The ideal soil depth for carrots is at least 12 inches (30 cm), though deeper soil (up to 18 inches or 45 cm) is even better for longer varieties.

Carrots thrive in loose, well-draining soil free from rocks or compacted layers, which can cause stunted or misshapen roots. A deeper soil bed allows the taproot to grow straight and strong, preventing forking or twisting.

For optimal results, mix sandy loam with compost to improve texture and fertility. Ensure the plant box has adequate drainage to avoid waterlogging, which can rot the roots. Regular watering and thinning seedlings to 2-3 inches apart will further promote robust growth.

By providing the right soil depth and conditions, your outdoor plant box can yield sweet, crisp carrots perfect for fresh eating or storage. Happy gardening!