When people first embrace urban gardening with planter boxes, enthusiasm often leads to a critical, plant-killing error: overwatering. It's the most common mistake by far. The instinct to constantly nurture can drown your plants. Unlike in-ground gardens, planter boxes have limited soil volume and rely entirely on their drainage holes. Overwatering saturates the soil, pushing out vital oxygen that roots need to breathe. This leads to root rot—a silent, fast-acting killer where roots turn mushy and brown, unable to absorb water or nutrients, causing the plant above to wilt despite wet soil.
The solution lies in mastering three fundamentals. First, ensure your boxes have ample, unblocked drainage holes. Second, use a high-quality potting mix designed for containers, never dense garden soil. Third, and most crucial, check the soil before watering. Insert your finger about an inch deep. If it feels moist, wait. Water only when the top layer is dry. It's better to underwater slightly than to overwater. By resisting the urge to water on a rigid schedule and instead responding to your plant's actual needs, you set the foundation for a thriving, green oasis in your urban space.