Repotting guide

When & how to repot Lithops Optica 'Rubra' (Lithops optica 'Rubra')

Also called purple living stones, rubra lithops.

More about lithops optica 'rubra'

About Lithops Optica 'Rubra'

Lithops optica 'Rubra' · also called purple living stones, rubra lithops · houseplant

Lithops optica 'Rubra' is a sought-after living stone with deep reddish-purple, club-shaped bodies and translucent windowed tops. Native to Namibia's coastal fog belt, it stays tiny, splits annually, and bears white-petalled flowers in late autumn. It prizes intense light, razor-sharp drainage, and a strict dry summer rest to keep its colour and prevent rot.

Mature size: Around 2-3 cm tall and wide per head; slow to form small clusters.

Watch for — Loss of red colour: Insufficient light reverts the body to green. Move to your brightest spot or add a strong grow light to restore the purple-red pigment.

How to tell lithops optica 'rubra' needs repotting

Repotting on a calendar is less reliable than reading the plant. For lithops optica 'rubra', watch for these signs:

Roots spiralling thickly out of the drainage holes or pushing the whole plant up out of the pot.
The pot is so packed that water runs straight through in seconds and barely wets the soil.
It has split a plastic pot, or the rootball is a solid mass with almost no soil left when you slide it out.
Growth and (for lithops optica 'rubra') flowering have clearly stalled despite good light and feeding — but remember this plant likes being snug, so a little crowding alone is not a reason to repot.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot lithops optica 'rubra'

Only every 2–4 years, when genuinely crowded. Lithops Optica 'Rubra' is one of the plants that genuinely prefers a snug pot — it grows and flowers better with its roots a little restricted, so resist the urge to repot it on schedule. Stemless, solitary or slowly clumping mesemb forming a single pair of fused, club-shaped leaves that renews itself once a year..

What size pot to step lithops optica 'rubra' up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Lithops Optica 'Rubra' positively prefers a snug pot: it flowers and grows better when the roots are a little restricted. The single biggest repotting mistake here is over-potting — dropping lithops optica 'rubra' into a pot two or three sizes up. All that surplus soil holds water the small root system cannot use, stays cold and wet, and rots the roots within weeks. When in doubt, choose the smaller pot.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot lithops optica 'rubra'

Early spring, just as new growth restarts, is the ideal window for lithops optica 'rubra'. The plant is moving into its strongest growth phase and re-roots into fresh soil quickly. Avoid repotting in winter dormancy or, for flowering plants, while it is in bud or bloom — recovery is slowest then and you risk dropping the flowers.

Step-by-step: repotting lithops optica 'rubra'

Confirm it actually needs it. Slide lithops optica 'rubra' out and check the roots. Only continue if it is genuinely packed — this plant prefers a snug pot, so if there is still soil and room, put it straight back.
Pick a pot only one size up. Choose a pot just 2–3 cm wider with good drainage. Resist anything bigger; over-potting is the main killer here.
Ease it out gently. Water lightly the day before, then tip lithops optica 'rubra' out, supporting the base. Tease the outer roots free only enough to stop them circling.
Repot at the same depth. Add a layer of fresh mineral, ultra-fast-draining grit mix, set the plant so the soil line sits exactly where it did before, and backfill around the sides, firming lightly.
Settle it in. Water once to settle the soil, then let it sit. Hold off on more water until the top of the soil dries — fresh soil around a small root system stays wet for a while.

Aftercare

Because the new soil holds more water than the old crammed rootball did, ease right back on watering — let the top of the soil dry before you water lithops optica 'rubra' again, or you will rot the roots in the very pot you just moved it to. Keep it out of harsh direct sun for a fortnight. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for lithops optica 'rubra'

Lithops Optica 'Rubra' wants mineral, ultra-fast-draining grit mix. At least 60% pumice, lava grit or coarse sand with minimal organic matter. 'Rubra' is especially rot-prone, so prioritise drainage above all. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting lithops optica 'rubra' — frequently asked questions

How often should you repot lithops optica 'rubra'?

Only every 2–4 years, when genuinely crowded for lithops optica 'rubra'. Only repot lithops optica 'rubra' every 2–4 years, and only when it is genuinely root-bound — it flowers and grows best slightly crowded. Step up just one pot size in spring using mineral, ultra-fast-draining grit mix. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does lithops optica 'rubra' need?

When is the best time of year to repot lithops optica 'rubra'?

Does lithops optica 'rubra' like to be root-bound?

Yes — lithops optica 'rubra' genuinely flowers and grows best when slightly pot-bound, so do not rush to repot it. The mistake to avoid is over-potting into a much larger pot: the excess soil stays wet, the roots cannot use it, and the plant rots. Only repot every few years and only one snug size up.

Should you fertilise lithops optica 'rubra' after repotting?

Not immediately. Wait about 4 weeks after repotting lithops optica 'rubra'. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.