How to Propagate Lithops from Seed and by Dividing Clumps

Three routes, one of which does not exist

Lithops break the rule that governs most succulents. A leaf laid on grit will not root and will not sprout, because each leaf is half of a single fused body with no growing point of its own. Cutting a body in half destroys it. If you have read that you can propagate succulents from leaves, set that knowledge aside completely for this plant.

What does work is seed, which is how the vast majority of cultivated lithops come into existence, and division of a clump that has produced multiple heads from one root system. Seed is slow but gives you dozens of plants from one sowing. Division is quick but only ever gives you what the plant already had.

Getting seed in the first place

Lithops flowers are almost entirely self-incompatible, meaning one plant on its own will not set seed even if you move pollen from one flower to another on the same plant. You need two genetically distinct plants flowering at the same time. Plants raised from the same seed packet may or may not count as distinct, so if you want seed, keep several unrelated plants and hope their flowering overlaps.

Pollination is easy when it does overlap. On a warm afternoon when both flowers are fully open, brush a soft dry paintbrush through one flower and then the other, going back and forth two or three times. A successful pollination closes the flower within a day or two and leaves a swelling capsule behind. The capsule then takes months to ripen and dry, and it stays closed until it gets wet, which is a rain-triggered dispersal mechanism. Harvest the dry capsule, drop it in water, and the segments open and release very fine seed.

Sowing, and why seedlings want the opposite treatment

Everything you know about keeping adult lithops dry is wrong for seedlings. For the first several months the seedlings have no reserves, no taproot and no ability to survive a dry spell, so the mix must stay lightly moist rather than drying out between waterings. This is the phase people fail, usually by applying adult discipline far too early. Autumn sowing suits most climates because it leads into the cooler growing season, but sowing works at any time of year if you can supply warmth and light.

1. Prepare a shallow pot of fine gritty mix Use the same mineral mix as for adults but sieved finer, around one to two millimeters, in a pot two to three inches (5 to 8 cm) deep with good drainage. Level the surface and soak the pot from below until the surface is damp all over.
2. Sow on the surface and do not cover The seed is dust-fine and needs light to germinate. Tap it thinly across the surface and press it down gently with a flat card so it sits in contact with the grit. Covering it with mix will stop germination outright.
3. Cover the pot, not the seed Put a clear lid, a bag or a sheet of glass over the pot to hold humidity, leaving a small gap for air. Keep it at 65F to 80F (18C to 27C), with warm days and cooler nights being ideal. Give it bright light but not scorching direct sun at this stage.
4. Expect germination in one to three weeks Seedlings appear as tiny green spheres barely a millimeter across, sometimes in flushes over several weeks. Keep the surface damp throughout this period by misting or by watering from below, never letting it dry completely.
5. Ventilate gradually from about six weeks Open the cover a little more each week over the course of a month, then remove it. Sudden uncovering wilts seedlings in a day. As the cover comes off, increase light steadily so the seedlings do not stretch.

Fungal damping off is the main loss in the first two months. Sterile mix, a thin sowing so the seedlings are not touching, and steady air movement once the cover is off prevent almost all of it. Crowded, still, warm and wet is the combination to avoid.

The first two years of a seedling

Through the first year, water lightly and often enough that the mix never dries right through, and give the strongest light the seedlings can take after acclimatisation. Do not prick them out during the first year; they resent disturbance and the tiny root systems intertwine harmlessly. They stay in the seed pot until they are crowded, which is usually somewhere between twelve and eighteen months.

The first leaf change comes at roughly a year old and is the moment the plant starts behaving like an adult. From that first change onwards, apply the adult rule and give no water while the new pair is forming. Losses at this stage are normal and it is not a sign you did anything wrong; a tray that started with fifty seedlings and holds thirty sturdy two-year-olds has done well. Flowering typically starts in the third or fourth year.

Dividing a clump, and what to write down

An older plant that has produced three or more heads from a single root mass can be split, and the right moment is the same as the right moment to repot: spring, after the old leaves are papery, or late summer before the growing season. Tip the plant out dry, crumble the mix away and look for the natural junctions. Some heads separate with their own roots simply by teasing them apart, and those are the ones to take. Where heads share a single taproot, cut with a clean blade so each division keeps some root, then let the cut surfaces dry in open air for three to five days before potting.

Pot each division into its own small deep pot in the standard mix and leave it dry for two weeks. Divisions with little root take longer to establish and may shrink noticeably before they recover, which is normal so long as they stay firm.

Record the sowing date and the date of first germination, the date you removed the cover, and how many seedlings survived to one year. For divisions, record the parent plant, the date and how much root each division kept. Seed-raised plants vary, and if you note which sowing a plant came from you can trace back which batch produced the shapes and colors you liked well enough to want more of.