To understand our light requirements, you must first understand where we come from. We are native to the arid, sun-scorched deserts and rocky plains of Southern Africa. Here, we grow in conditions of intense, direct sunlight for most of the day, with very little shade from other vegetation. Our unique, stone-like appearance is a masterclass in evolution, providing camouflage from thirsty herbivores. More importantly, our two thick, fused leaves are designed to act as living solar panels and water reservoirs. They are precisely engineered to harness and tolerate powerful sunlight, which is the primary energy source we use to fuel our entire life cycle, including the crucial process of photosynthesis that occurs deep within the translucent "windows" on our leaf tops.
Sunlight is not merely a preference for us; it is the absolute cornerstone of our existence and dictates our annual rhythm. Adequate, direct sun exposure is what triggers and sustains our growth phases. During our active growth periods in autumn and spring, strong light ensures we photosynthesize efficiently, building up the internal moisture and nutrients we need to survive. Most critically, the intense light of late summer and autumn is the environmental cue that initiates the development of our beautiful white or yellow flowers. Without sufficient light, we simply will not bloom. Furthermore, strong light is essential for maintaining our compact, stone-like form. In low light conditions, our bodies will become etiolated—stretched, pale, and misshapen—as we desperately reach for a light source, severely weakening our structure.
When living in your care as a potted plant, we strive to replicate our native environment as closely as possible. Our ideal location is a windowsill that receives direct sunlight for a significant portion of the day. A south-facing window is perfect in the Northern Hemisphere, while a north-facing window is ideal in the Southern Hemisphere. We require a minimum of 4 to 5 hours of direct sunlight daily, though we truly thrive with 6 or more hours. The intense light of the morning sun is always beneficial. During the peak intensity of a summer afternoon, especially in very hot climates, a tiny amount of filtered light (such as through a sheer curtain) can prevent potential sun scorch on our surfaces, but this is not always necessary if we have been properly acclimated.
It is paramount that you never move us abruptly from a low-light situation directly into hours of intense, direct sun. Our tissues, while adapted for sun, can still suffer severe sunburn if shocked. This appears as permanent white, crispy, or brown scarred patches. If we are new plants or have been kept in shade, you must acclimate us gradually. Start by giving us just an hour or two of direct morning sun for a week, then slowly increase the exposure by about an hour each subsequent week until we are receiving our full daily requirement. This gradual process allows our internal systems to adjust and build up a natural tolerance, just as we would in the wild as seedlings growing slightly shaded by a rock.
