Living stones care guide

Living stones are tiny succulents that look like pebbles. Each plant is one pair of thick, fused leaves with a split across the top. They come in gray, tan, green, rust, and purple, often with patterns on top. In the wild, in South Africa, they blend in with the stones around them. In fall, a yellow or white daisy-like flower pops out of the split.

Living stones are easy once you learn their calendar. Most die from water at the wrong time.

Light

Give them the sunniest spot you have. A south window is best. They need four or more hours of direct sun.

In low light, they stretch tall and lean, and the leaves lose their flat tops. A grow light helps in winter.

The watering calendar

Lithops grow on a cycle. Water to match it, not by the calendar on your wall.

• Late summer and fall: growing season. Water when the soil is fully dry, about every two to three weeks. This is when they plump up and flower.
• Winter: leaf change. A new pair of leaves forms inside the old pair. Stop watering. The new leaves drink from the old ones.
• Spring: old leaves shrivel. The old pair splits open and dries to a papery shell. Do not water until the old leaves are fully dry. Then give a small drink only if the new pair wrinkles.
• Summer: rest. Growth stops in the heat. Give little or no water. A small drink once a month is plenty if they wrinkle hard.

If you water during the leaf change, the old leaves do not shrink. You end up with two pairs stacked on top of each other. Too much water at any time can make the leaves split or burst. Read how to tell if a houseplant is overwatered or underwatered.

Soil and potting

Use a gritty mix that is at least half pumice, coarse grit, or perlite. Mix it with cactus soil.

They have long taproots. Use a deep pot with a drainage hole. Clay pots help the soil dry out. Grow several together in one pot for a stone garden look.

Repot only every few years, in summer or early fall. See how to repot a houseplant step by step.

Humidity and temperature

Dry indoor air is fine. Keep them between 18 and 27°C (65 and 80°F). Cool winters, down to 10°C (50°F), are fine while they are dry. Keep them above 5°C (40°F).

Feeding

They need little food. Feed once a year in fall with a cactus fertilizer at quarter strength, or skip it. Too much food makes them grow soft and lose their shape.

Flowers

Healthy, mature plants flower in fall. A bud pushes up from the split between the leaves. It opens into a yellow or white flower in the afternoon and closes at night, for a week or so. Cut it off once it dries.

Propagation

Most lithops are grown from seed. Seed is slow. It takes three to four years to reach flowering size.

Older plants can split into clumps with several heads. Each head has its own roots. Divide a clump in late summer, before the growing season, and let the cuts dry for a few days before potting.

Problems

What you see	Most likely cause
Leaves split or burst	Too much water
Soft, mushy, see-through leaves	Rot from too much water
Two pairs stacked on top of each other	Watered during the leaf change
Stretched tall, leaning	Not enough light
Old leaves shrivel in winter and spring	Normal leaf change
Wrinkled in fall	Thirst. Water.
White, cottony spots	Mealybugs

Pests

Mealybugs are the most common pest. They hide in the split and around the base. Root mealybugs live in the soil. Fungus gnats show up when the soil stays wet. See how to get rid of fungus gnats in houseplants.

Pet safety

Living stones are not on the ASPCA list of toxic plants. They are often sold as pet safe. They are small enough that a pet could swallow one whole, so keep them out of reach.

Varieties

• Lithops lesliei has tan to rust tops with dark patterns. It is one of the easiest to grow.
• Lithops karasmontana has pale tops with rusty lines.
• Lithops aucampiae has rich brown tops and grows larger.
• Lithops optica ‘Rubra’ has purple-red leaves with clear windows on top.
• Lithops dorotheae has yellow-tan tops with red marks.