Lithops, commonly known as living stones, are supremely adapted to survive extended periods without water. This ability is not a simple tolerance but a complex, evolved survival strategy. They are native to the arid deserts of southern Africa, where rainfall is infrequent and unpredictable. Their entire morphology and life cycle are engineered to conserve every possible drop of moisture. The plant's body consists of a pair of fused, succulent leaves that are mostly subterranean. This design minimizes surface area exposed to the harsh, desiccating sun and wind. These leaves function as water storage organs, holding all the moisture and nutrients the plant needs to endure months of drought.
The plant's water needs are intrinsically tied to its unique growth cycle. Lithops can go without any additional water for the entire duration of their dormancy period, which typically spans through the summer and sometimes into early autumn. This dormancy is a protective measure against excessive heat and water loss. During this time, which can last 4-5 months or even longer, the plant relies entirely on the moisture stored in its leaf pair. Watering during this phase is detrimental, as the plant is not actively growing and the excess moisture can lead to fatal rot. The plant's metabolism slows significantly, and it effectively waits for more favorable conditions.
A critical period where Lithops must remain dry is during its molting phase, which usually occurs in late winter or spring. This is when a new pair of leaves emerges from the fissure between the old leaves. The new growth is fueled by the water and nutrients reabsorbed from the old leaf pair. Throughout this process, which can take several weeks to months, the plant should receive absolutely no water. The old leaves gradually shrivel and dry into a papery sheath, transferring their stored resources to the new body. Providing water interrupts this natural process, potentially causing the old leaves to remain succulent and hindering the development of the new plant, making it susceptible to malformation and disease.
Under cultivation, a healthy adult Lithops can easily go without water for four to six months during its dormancy and molting periods. In their natural habitat, this duration can be even longer, potentially surviving an entire year or more on a single rainy season if conditions are exceptionally dry. The exact timeframe is influenced by factors such as the plant's size (larger plants store more water), the temperature (hotter conditions may accelerate water usage through minimal transpiration), and the humidity of the environment. However, their survival is not indefinite. They are not storing water for an endless drought but for a predictable seasonal cycle. Eventually, the stored reserves will be depleted, and the plant will begin to shrivel excessively, signaling the need for the next growth period and its accompanying watering season.
