Greetings, plant enthusiast. We are Lithops, the living stones. To thrive in your care, we require a very specific home for our roots. Our survival depends on it. Our native habitat is the harsh, arid, and incredibly well-draining mineral deserts of southern Africa. Our roots are highly susceptible to rot if left in moisture for even a short period. Therefore, our soil must be an inorganic, gritty, and fast-draining mix that mimics our natural conditions. Here is how you can create it using ingredients commonly available in the United States.
Our soil mix must be primarily composed of inorganic, non-water-retentive materials. This ensures rapid drainage and provides crucial aeration to our sensitive root systems. The goal is to have the soil dry out completely within just a few days after watering. Ideal components for this base include poultry grit (crushed granite), which is inexpensive and available at farm supply stores; pumice, a lightweight volcanic rock that is highly porous; and coarse silica sand (also known as horticultural or blast sand), which has large, sharp particles that prevent compaction. Perlite can be used as a partial substitute for pumice, but be aware it is very light and can float to the top over time. Avoid any materials that are soft, water-absorbent, or fine, like peat moss, vermiculite, or play sand, as they will compact around our roots and cause them to suffocate and rot.
A small amount of organic material is necessary to provide minimal nutrient holding capacity and a tiny bit of moisture retention for the very short term. However, this component must be chosen carefully. The best option is a well-draining succulent & cactus potting mix. Do not use it straight from the bag. You must sift it thoroughly to remove all the large chunks of wood, peat, and other spongy materials. What you want is the finer, soil-like portion. Alternatively, a small amount of coconut coir can be used, as it is less prone to compaction than peat, but it must also be used very sparingly. This organic fraction is not our food; it is merely a minor buffer. Our primary sustenance comes from the careful, infrequent watering you provide and the light we absorb.
To construct our ideal substrate, combine the ingredients in the following ratio by volume: 4 parts inorganic grit (e.g., 2 parts poultry grit, 1 part pumice, 1 part coarse sand) to 1 part sifted succulent potting mix. This creates an approximate 80%/20% mix. Combine all components in a large tub and mix them thoroughly until they are uniformly distributed. The final mix should be loose, gritty, and incapable of holding a shape if you squeeze a handful. It should fall apart immediately. Before potting us in this new mix, ensure our pot has a generous drainage hole. Place a piece of screen or a mesh coffee filter over the hole to prevent the soil from washing out. Then, pot us up, gently firming the mix around our taproot.
After potting, we highly recommend a top dressing of a small, attractive gravel or more poultry grit. This layer serves multiple vital functions: it keeps our body from sitting directly on damp organic matter, which can lead to stem rot; it stabilizes the soil surface, preventing the lighter components from shifting or blowing away; and it greatly reduces the chance of fungal gnats finding a home in our pot. Most importantly, it completes the aesthetic, making our pot look like the beautiful, minimalist desertscape we naturally belong in.
