Watering plants in urban planter boxes requires a different approach than watering those in the ground. The core difference lies in the limited soil volume. Planter boxes dry out significantly faster due to increased exposure on all sides, leading to more evaporation and quicker root absorption of available moisture. As a general rule, plants in planter boxes need watering more frequently—often daily during hot, dry, or windy summer weather—compared to in-ground plants, which may only need deep watering once or twice a week.
Several factors intensify this need. The material of your planter matters; porous terracotta loses moisture faster than plastic or glazed ceramic. Smaller boxes dry out quicker than larger ones. Sun exposure, wind, and season dramatically affect the rate. A simple finger test is the best guide: insert your finger into the soil up to the second knuckle. If it feels dry, it's time to water. Always water deeply until you see it drain from the bottom, ensuring the entire root ball is moistened. For in-ground plants, the larger soil mass acts as a reservoir, providing buffer and stability against rapid drying. By understanding these principles, you can adjust your routine to keep both your planter box and garden bed plants healthy and hydrated.