Watering is the lifeline of your garden, but the rules change dramatically between urban planter boxes and traditional in-ground beds. The core principle is simple: planter boxes dry out much faster. Their confined soil volume heats up quickly, has more surface area exposed to air, and offers limited water retention compared to the vast, cool earth.
For in-ground plants, deep, infrequent watering is king. This encourages strong root growth as they seek moisture deeper in the soil. You might water once or twice a week, depending on weather and soil type, always checking that the top few inches are dry before watering again.
Planter boxes, however, demand a more vigilant approach. In hot or windy urban settings, they may need watering daily, sometimes even twice a day during peak summer. The key is to check the soil daily. Insert your finger about an inch deep. If it feels dry, it's time to water. Always water thoroughly until you see excess water drain from the bottom—this ensures the entire root ball is hydrated.
To reduce frequency for your planter boxes, use a high-quality potting mix designed for containers, incorporate water-retaining crystals or organic matter like coco coir, and consider self-watering planters. Mulching the soil surface is also a highly effective tactic to slow evaporation.
Ultimately, forget a fixed schedule. Your plants' needs are dictated by sun, wind, heat, and the container's size. By understanding that planter boxes are thirstier and committing to the simple finger test, you'll master the art of watering in any urban space.