Lithops, often called "living stones," are masterful survivors adapted to the harsh, arid climates of southern Africa. Their growth cycle is a direct response to their native environment, and understanding this cycle from the plant's perspective is the key to knowing when to withhold water. Their dormancy is not a period of simple rest but a crucial survival strategy to endure extreme heat or cold with minimal resources.
From the plant's point of view, the decision to enter dormancy is triggered by two primary factors: photoperiod (day length) and temperature. As daylight hours shorten and temperatures begin to drop significantly in autumn, the Lithops receives a clear signal that the favorable growing season is ending. Internally, it starts to slow down its metabolic processes. The most important visual cue it gives you is the cessation of growth. The outer leaves will stop plumping up after watering, and the plant will simply not appear to be actively developing. This is the plant telling you it is preparing for its long sleep.
The most critical phase in the Lithops' annual cycle is the development of a new leaf pair from within the fissure between the old leaves. As the new body grows, it diligently draws all the stored water and nutrients from the old, outer leaves. From the plant's perspective, this is how it survives the dormant period; it is living off the resources contained in those sacrificial leaves. You must observe this process closely. The moment you see the old leaves begin to soften, wrinkle, and shrink while the new pair is visibly plump and growing, the plant has initiated its own water-recycling system. Adding external water at this point is not only unnecessary but actively harmful. It interrupts this natural process, confusing the plant's physiology and often causing the old leaves to remain engorged, which can lead to rot and hinder the new leaves' development.
While observing the plant's cues is paramount, a general seasonal guideline aligns with its internal rhythm. For the primary dormancy period (winter rest), you should typically stop watering in early to mid-autumn. This allows the plant to fully utilize any final late-season rainfall from its native habitat's simulation and begin to dry out as temperatures fall. Watering is then completely withheld throughout the winter months. For the secondary, often less strict, summer dormancy, watering is usually reduced and then stopped as temperatures consistently exceed 90°F (32°C) in summer. During peak heat, the plant's roots are largely inactive, and water in the soil will not be absorbed, instead creating a soggy environment that promotes fatal root rot.
The decision to stop watering is intrinsically linked to the soil's condition. A Lithops requires a mineral-based, extremely well-draining substrate—often 80-90% inorganic material like perlite or pumice. From the root's perspective, this medium is perfect because any accidental water applied too late in the season, or a light winter rain, will drain away almost instantly. It does not hold onto moisture around the sensitive taproot. In a organic-rich, moisture-retentive soil, the command to "stop watering" becomes far more critical and time-sensitive, as the medium will hold that dangerous moisture for days or weeks, directly contradicting the plant's need for a dry, dormant root system.
