Lithops, often called “living stones,” are unique succulents native to the arid regions of southern Africa. Their adaptations allow them to thrive in harsh desert environments. Temperature significantly influences their health, growth, and survival, making understanding their thermal needs essential for successful cultivation.
Optimal Temperature Ranges
For Lithops to thrive, specific temperature ranges are beneficial. During active growth, typically in cooler seasons, Lithops prefer daytime temperatures between 65°F and 80°F (18-27°C). These temperatures support optimal metabolic processes, allowing plants to efficiently convert light energy for growth.
A distinct day-night temperature differential is advantageous, mimicking their natural desert habitat. Ideally, nighttime temperatures should drop below 50°F (10°C) for healthy growth and to prevent etiolation. This fluctuation helps regulate internal processes, preparing them for the next day’s light exposure and supporting their unique growth cycle.
Temperature Tolerance and Extremes
Lithops tolerate temperatures outside their optimal range, but prolonged exposure to extremes can cause stress or irreversible damage. They generally tolerate temperatures up to 90°F to 100°F (32-38°C) for short durations. Sustained temperatures above this can induce dormancy, causing plants to shrivel or leading to scorching and tissue damage.
On the colder end, Lithops are sensitive to low temperatures. Temperatures consistently below 50°F (10°C) are not recommended, and exposure below 40°F (4°C) can cause significant frost damage. Freezing temperatures can rupture cell walls, leading to soft, mushy leaves, rot, and death. Signs of heat or cold stress include wrinkling, shriveling, browning or yellowing of leaves, or a complete halt in growth.
Seasonal Temperature Considerations
Lithops temperature requirements fluctuate with their annual growth and dormancy cycles, cued by seasonal shifts. As autumn approaches and temperatures cool, Lithops emerge from summer dormancy and enter an active growth phase. This period, typically late summer through fall, is when new leaves emerge, absorbing moisture from the old pair, and many varieties flower.
During winter, as temperatures remain cooler, new leaves continue to develop, nourished by stored resources in older leaves. Lithops often enter a second, drier dormancy during the hottest summer months, conserving water and energy. These temperature cues influence processes such as flowering, leaf splitting, and water uptake.
Managing Temperature for Lithops
Maintaining appropriate temperatures for Lithops in a home environment involves several strategies. For indoor cultivation, placing plants in a south-facing window provides ample light and warmth. However, avoid intense, direct midday sun, which can lead to scorching, especially behind glass. Good air circulation, possibly with small fans, prevents heat buildup and reduces detrimental humidity.
For outdoor Lithops, protection from extreme conditions is necessary. During intense heat, providing partial shade, particularly in the afternoon, helps prevent leaf burn and stress. As temperatures drop in late fall or winter, frost protection is crucial. This may involve covering plants with frost cloth or bringing them indoors when temperatures are consistently below 50°F (10°C) or approach freezing. Regularly monitoring ambient temperatures with a thermometer ensures Lithops remain within their preferred range.