From our perspective as Black-eyed Susans (Rudbeckia hirta), thriving in a container is a different experience compared to living in the ground. Our roots are confined, unable to seek out moisture from a large volume of soil. This makes your watering routine the single most crucial factor for our health and happiness. We cannot tell you the exact number of days, but we can tell you how to read our needs.
Please do not water us on a rigid schedule. The frequency changes with the weather, the season, and our growth stage. The most reliable method is to physically check the moisture level in our pot. Insert your finger into the soil up to the second knuckle (about 2 inches deep). If the soil at that depth feels dry, it is time for a thorough watering. If it still feels cool and moist, please wait and check again in a day or two. We appreciate consistent moisture, but our roots absolutely despise sitting in constantly soggy, waterlogged soil, which will cause them to rot and ultimately kill us.
Several external factors dramatically affect how quickly we use water. On hot, sunny, and windy days, we photosynthesize rapidly and lose moisture through our leaves (transpiration), meaning we will need water much more frequently—potentially every day during a heatwave. Conversely, during cool, cloudy, or rainy periods, our soil will stay moist for longer, and we will require less frequent watering. The size of our pot also matters; a smaller pot dries out exponentially faster than a large one. Furthermore, as we grow and become root-bound, the ratio of roots to soil increases, leaving less material to hold water, which also increases our watering needs.
When we are thirsty, we need a deep, satisfying drink. Water us slowly at the base, avoiding our leaves to prevent fungal diseases. Continue watering until you see excess water freely draining out of the holes at the bottom of the pot. This ensures that the entire root ball has been evenly moistened. Empty the saucer underneath after about 30 minutes to ensure we are not left standing in water. A pot with excellent drainage is non-negotiable for our survival.
Our water needs change with our annual cycle. During our active growing and blooming season (spring and summer), we are putting immense energy into flowering and will require the most consistent watering. As autumn arrives and our growth slows, you should gradually reduce the frequency. In winter, if we are in a dormant state, our soil should be kept on the drier side; water only sparingly to prevent the roots from completely desiccating, as we are barely drinking at all.
