To understand if we can live outdoors, you must first understand where we come from. We are native to the hot, arid deserts and rocky outcrops of South Africa and Namibia. Our natural environment is characterized by intense, bright sunlight, very little rainfall, extremely well-draining sandy or gravelly soil, and low humidity. We have evolved to survive in these harsh conditions by storing water in our leaf pairs and by growing almost completely submerged in the ground, with only our windowed tops exposed to absorb sunlight. Any attempt to grow us outdoors must replicate these specific conditions as closely as possible to ensure our survival.
Our foremost concern outdoors is temperature. We are highly susceptible to rot and cellular damage from cold, wet conditions. We simply cannot tolerate frost. From a hardiness zone perspective, we can only survive year-round outdoors in the warmest regions of the United States. This typically means zones 10a and above, where average minimum winter temperatures stay above 30°F (-1.1°C). In zones 9b, it is a borderline case and would require a perfectly sheltered microclimate, excellent drainage, and protection from any chance of frost or winter rain. For the vast majority of the U.S., we are not cold-hardy and must be grown in containers that can be brought indoors for the winter.
Even in a suitable zone, the soil is often our downfall. Garden soil, even amended soil, is too rich and retains too much moisture for our roots, which are designed to seek water deep below the surface and then dry out completely. To grow us outdoors successfully, you must create a specialized planting bed or use a raised mound. The substrate must be overwhelmingly inorganic. A mix of 80-90% mineral grit like pumice, coarse sand, or perlite, with only 10-20% potting soil or coconut coir, is ideal. This ensures water flows through instantly, mimicking our native gritty quartz fields and preventing fatal root rot.
Our sunlight needs are high, but our tolerance is specific. We require several hours of direct sunlight daily to maintain our compact shape and vibrant patterns. However, in extremely hot, low-humidity desert zones (like parts of Arizona), the intense afternoon sun can sometimes scald our tops. A location with full morning sun and light afternoon shade can be perfect. Regarding water, our outdoor schedule is dictated entirely by the seasons and never by the calendar. You must withhold almost all water during our summer dormancy and during the winter. The only safe time to water is during our growth periods in autumn and spring, and only if the weather is sunny and warm, allowing the soil to dry within a day or two.
Perhaps the biggest challenge to growing us outdoors, even in a warm zone, is ambient humidity and unexpected rainfall. Our bodies are designed to absorb moisture from fog and dew, not from saturated soil. Prolonged rain, especially during our dormant summer period or cool winter months, is a death sentence. It causes our bodies to absorb too much water, leading to fatal splitting and rot. If you live in a zone with summer thunderstorms or winter rains, you must provide overhead protection, such as a clear rain cover or by planting us under the eaves of a roof or a covered patio. Good air circulation is also crucial to help our soil surface dry quickly after any watering or dew.
