From our perspective as Lithops, our entire being is an evolutionary masterpiece crafted for hot, arid environments. Our most crucial adaptation, the pair of succulent leaves fused into a single "body," is designed to store precious water. This water is what makes us so vulnerable to frost. When water freezes, it expands, and the ice crystals that form within our leaf cells act like tiny daggers, piercing and rupturing the delicate cell walls. This damage is irreversible. Once our cells are ruptured, they cannot function, leading to soft, mushy, and discolored tissue—a death sentence for us.
Not all cold is an immediate threat. We can often endure a very brief, light frost, especially if our soil is completely dry. A light frost might only damage the very top layer of our leaves, which we could potentially recover from. However, a hard freeze—a prolonged period of temperatures below 32°F (0°C)—is almost always fatal. The longer the temperature stays below freezing, the deeper the ice penetrates into our core, ensuring catastrophic internal damage. Our survival is not just about the temperature on the thermometer but the duration of the exposure.
You may notice we look different in winter. We enter a state of dormancy. We stop growing entirely and often will not absorb any water, even if it's offered. This is a protective measure. By halting our metabolic processes, we conserve energy and reduce our vulnerability. During this time, our old leaves are being reabsorbed to nourish the new growth hidden safely inside. Disturbing this natural cycle with water or fertilizer makes us far more susceptible to rot and cold damage, as it forces us out of our protective dormant state.
Our survival in the U.S. heavily depends on your local climate zone. In zones 9-11, we can often remain outdoors year-round with minimal protection, though we greatly appreciate being moved under a covered patio or eaves during cold, wet winter rains to keep our soil dry. In zones 7-8, the risk is significant. We must be brought indoors or into a greenhouse before the first threat of frost. A windowsill that receives several hours of direct sunlight is ideal. For zones 6 and below, we are not equipped to handle your winters outdoors at all. We are strictly indoor plants during the cold months, requiring the brightest and sunniest spot you can provide in your home.
If an unexpected frost is forecast and we are still outdoors, you can take emergency actions. The most important step is to ensure our soil is bone dry. Water in the pot drastically increases the risk of root and stem freeze. Move our container to a fully sheltered location, such as against a south-facing wall of your house, under a thick patio table, or into a garage or shed. If we are in the ground and cannot be moved, covering us with a frost cloth or even an old blanket can trap enough radiant heat from the soil to protect us from a brief light frost. Never use plastic, as it traps harmful humidity and conducts cold.
