From our perspective, the answer to your watering frequency is not a simple schedule but a state of being. We, Black-eyed Susans (Rudbeckia hirta), are native to the open meadows and prairies of North America. Our roots are adapted to conditions that are generally well-draining yet receive regular rainfall. We are inherently drought-tolerant once established in the ground, with deep root systems that seek out moisture. However, our existence in a pot fundamentally changes this dynamic. Our root system is confined, unable to explore a large volume of soil for water, making us entirely dependent on your care. The pot becomes our entire world, and its environment dictates our health.
You must learn to read our language, which is spoken through the soil. The most common cause of our demise in containers is not underwatering, but overwatering. Soggy, waterlogged soil suffocates our roots, preventing them from absorbing oxygen and leading to fatal root rot. Therefore, the universal rule is to water only when the top inch of the soil feels dry to the touch. Insert your finger into the potting mix up to your first knuckle. If the soil at that depth feels dry, it is time to water. If it still feels cool and moist, we are content and do not need a drink. This "finger test" is far more reliable than adhering to a rigid calendar schedule.
Several external factors dramatically alter how quickly we use the available water in our pot. You must observe and adjust your care based on these conditions:
Sunlight and Temperature: We are sun-loving plants. If our pot is placed in full sun (6+ hours of direct light), especially during the peak of summer, the soil will dry out very quickly, sometimes requiring water daily. In cooler, cloudier weather, or if we are in partial shade, our water consumption slows significantly.
Pot Size and Material: A small pot or a hanging basket dries out much faster than a large, deep container with more soil volume. Furthermore, pots made of porous materials like terracotta or clay allow moisture to evaporate through their walls, speeding up the drying process. Plastic or glazed ceramic pots retain moisture for a longer duration.
Season and Growth Stage: Our thirst is greatest during the intense heat of mid-summer and when we are actively growing and flowering, as this process consumes significant energy and water. In the spring as we establish and in the autumn as we begin to fade, our water requirements will decrease.
When it is time to water, please do so thoroughly. Apply water slowly to the base of the plant, avoiding wetting our foliage, which can encourage fungal diseases. Continue watering until you see a steady stream of water escaping from the drainage holes at the bottom of the pot. This ensures that the entire root ball has been evenly moistened. Allow all excess water to drain away completely. Never let us sit in a saucer full of standing water, as this will lead to the root rot we fear.
