Lithops, often called “living stones” or “pebble plants,” are a unique group of succulents. Their camouflage-like appearance allows them to blend seamlessly with rocky surroundings in their native arid environments.
What Makes Lithops Unique
Lithops are distinct due to their mimicry of stones and pebbles, a survival mechanism against herbivores in their natural Southern African habitat. Each plant typically consists of two fleshy leaves, almost fused, forming a compact, stone-like body. A notable feature is the translucent “window” on the top surface of their leaves, which allows light to penetrate to green photosynthetic tissue located inside the plant, enabling photosynthesis even when most of the plant is buried.
Caring for Your Lithops Plant
Lithops thrive when provided with specific environmental conditions that replicate their dry, rocky origins.
Light Needs
Lithops require abundant bright light, ideally four to five hours of direct sunlight daily. A south-facing window is often the best indoor location, or an unobstructed eastern exposure. While they tolerate strong light, extreme midday sun can potentially scorch their foliage, so some partial shade during the hottest parts of the day may be beneficial. Insufficient light can lead to etiolation, causing the leaves to stretch and lose their compact shape and vibrant patterns.
Watering Principles
Watering Lithops is the most specific aspect of their care, as overwatering is the primary cause of their demise. These plants store significant water in their leaves, allowing them to survive for months without additional moisture. Water sparingly, only when the plant shows signs of needing it, such as slight shriveling or wrinkling on its sides. When in doubt, delay watering. Watering should primarily occur during active growth phases, with dry periods enforced during dormancy and splitting cycles to prevent rot.
Ideal Soil and Potting
Lithops require an extremely well-draining, gritty soil mix to prevent water retention and promote healthy root development. A suitable medium typically consists of a high percentage of inorganic materials like pumice, perlite, coarse sand, gravel, or decomposed granite, with very minimal organic matter. While Lithops have a taproot system, pots 3 to 5 inches deep are generally recommended to accommodate their roots without holding excessive moisture.
Temperature and Air Humidity
Lithops prefer warm temperatures during active growth, typically thriving between 65 to 80 degrees Fahrenheit. They can tolerate higher temperatures, even up to 90-100 degrees Fahrenheit, but good air circulation is beneficial. During dormant periods, they can withstand cooler temperatures, but protection from freezing conditions below 40 degrees Fahrenheit is advised. Low air humidity is ideal for Lithops, mirroring their natural desert environments.
Feeding Your Lithops
Lithops rarely require fertilization, as they are adapted to nutrient-poor, rocky soils. If fertilizer is used, it should be highly diluted, such as a very weak solution of a low-nitrogen, high-potassium cactus fertilizer. Fertilize infrequently, often just once a year before blooming to encourage flowers. Avoid direct contact of fertilizer with the plant’s leaves to prevent damage.
The Lithops Growth and Splitting Cycle
Lithops undergo a distinctive annual growth cycle, which directly dictates their watering needs. New leaves begin to develop inside the existing pair during winter, and as spring approaches, older leaves split apart, revealing new, larger leaves emerging from the fissure. During this “splitting” process, the new leaves absorb moisture and nutrients from the old ones, causing the old leaves to shrivel and dry into papery husks. Withhold water completely during this period, even if the plant appears shriveled, as watering too early can disrupt absorption and lead to rot. Once old leaves have completely withered, light watering can resume, generally in late summer or early autumn, leading into their flowering period.
Troubleshooting Common Lithops Issues
Lithops can experience specific problems, mostly related to their unique care requirements. Overwatering is the most frequent issue, leading to a mushy, rotten appearance of the plant; leaves may become soft, yellow, or even burst, so prevent this by adhering strictly to dry periods and ensuring excellent drainage. Conversely, underwatering causes shriveling or wrinkling, but distinguish this from normal splitting cycle shriveling; if not splitting, a light watering may restore plumpness. Lack of splitting or abnormal growth like etiolation points to insufficient light or too much water, and providing adequate light from the start is important as etiolation is largely irreversible. Pests and diseases are less common, but root rot is a concern, typically caused by persistent overwatering; maintaining proper soil conditions and a strict watering regimen helps prevent such issues.