During a heatwave, your urban planter boxes need extra attention. The general rule is to check them daily, as containers dry out much faster than in-ground gardens, especially on balconies or rooftops exposed to full sun and reflected heat.
Don't rely on a fixed schedule. Instead, perform the finger test: insert your finger into the soil up to the second knuckle. If it feels dry, it's time to water. The goal is deep, thorough watering early in the morning, ideally before 9 AM. This allows water to reach the entire root zone before the day's heat causes rapid evaporation. Avoid watering in the evening, as prolonged moisture on leaves can encourage fungal diseases.
Signs your plants need immediate water include wilted, limp leaves and dry, pulling-away soil from the container edges. For larger boxes, water slowly until you see it drain freely from the bottom, ensuring the roots are fully quenched.
To reduce watering frequency, use mulch (like bark chips or straw) on the soil surface to retain moisture. Consider providing afternoon shade with a sun cloth or temporarily moving smaller boxes to a cooler spot. Always use containers with adequate drainage holes to prevent root rot.
By monitoring diligently and watering deeply in the cool morning hours, you can help your urban garden not just survive, but thrive through the summer's hottest waves.