To create the perfect humidity environment for us, you must first understand our origins. We are native to the fynbos regions of South Africa, a land characterized by well-drained, acidic, mineral-rich soils and a Mediterranean climate. This means we are adapted to summers that are hot and dry, not hot and humid. Our leaves and roots are designed to extract minimal moisture from the air and soil. High ambient humidity is foreign to our physiology and creates a significant threat to our health and longevity.
The single most important factor for our survival is excellent air circulation combined with low to moderate humidity levels. Stagnant, moist air is our greatest enemy. It creates the perfect breeding ground for fungal pathogens like Botrytis cinerea (gray mold) and Phytophthora, which can quickly lead to root rot and fatal stem cankers. Our roots are exceptionally efficient at water uptake but highly susceptible to waterlogging. Therefore, humidity must be managed in tandem with perfectly draining soil. Good airflow around our foliage helps to keep the leaf surface dry, disrupting the spore cycle of fungi and mimicking the breezy conditions of our native hillsides.
When the air is too humid, our transpiration process slows down dramatically. Transpiration is how we cool ourselves and move nutrients through our systems. When this process is inhibited due to saturated air, we become stressed, lethargic, and our growth can be stunted. Furthermore, constantly damp conditions on our stems and leaves invite fungal infections that manifest as black spots, wilting, and dieback. For potted specimens indoors, placing us near a humidifier intended for tropical plants would be a fatal mistake. We thrive in the same dry air that most houseplants dislike.
Outdoors, plant us in a elevated position or a sloping bed to ensure water drains away quickly. Space us adequately to allow air to move freely between each plant, preventing a humid microclimate from developing within the foliage. Avoid overhead watering, especially in the evening, as this leaves water sitting on our leaves overnight. Instead, use drip irrigation or water at the base in the morning. For greenhouse cultivation, proper ventilation is non-negotiable. Vents, exhaust fans, and circulation fans are essential to prevent humid air from settling around us. In dry climates, our natural humidity preferences are easily met, but in more humid regions, selecting a planting site with maximum sun exposure and breeze is crucial.
