Repotting guide

When & how to repot Argyroderma delaetii (Argyroderma delaetii)

Also called silver skin plant, bum plant.

More about argyroderma delaetii

About Argyroderma delaetii

Argyroderma delaetii · also called silver skin plant, bum plant · houseplant

Argyroderma delaetii, nicknamed the bum plant for its smooth, paired silver-green leaves cleft down the middle, is a winter-growing mesemb from the Knersvlakte quartz fields of South Africa. It opens magenta, yellow or white daisy-like flowers from late autumn into winter. It needs very bright light, a pure mineral mix and water timed to its cool-season growth.

Mature size: About 3-5 cm tall and 4-8 cm across; clumps stay under roughly 10 cm wide.

Watch for — Mealybugs: Cottony pests lodge in the central cleft and around roots. Inspect at repotting, isolate new plants, and treat with isopropyl alcohol.

How to tell argyroderma delaetii needs repotting

Repotting on a calendar is less reliable than reading the plant. For argyroderma delaetii, watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

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 argyroderma delaetii

Every 2–3 years, into bone-dry mix. Argyroderma delaetii's growth habit — dwarf, slow, clump-forming mesemb. forms one to several pairs of fused, near-spherical to egg-shaped silvery leaves on a short stem, slowly building into a small mound. — sets the pace. Argyroderma delaetii, nicknamed the bum plant for its smooth, paired silver-green leaves cleft down the middle, is a winter-growing mesemb from the Knersvlakte quartz fields of South Africa. It opens magenta, yellow or white daisy-like flowers from late autumn into winter. It needs very bright light, a pure mineral mix and water timed to its cool-season growth.

What size pot to step argyroderma delaetii up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Argyroderma delaetii stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

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 argyroderma delaetii

Spring or summer, while argyroderma delaetii is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting argyroderma delaetii

Repot dry. Do not water argyroderma delaetii for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty sandy, gritty mineral mix in a deep pot ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set argyroderma delaetii at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep argyroderma delaetii completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for argyroderma delaetii

Argyroderma delaetii wants sandy, gritty mineral mix in a deep pot. Use 70-80% mineral grit (coarse sand, pumice, perlite) with a small amount of cactus compost; in habitat it grows in quartz gravel. A deep pot with a drainage hole accommodates the taproot. Rich, moisture-retentive soil causes rot. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting argyroderma delaetii — frequently asked questions

How often should you repot argyroderma delaetii?

Every 2–3 years, into bone-dry mix for argyroderma delaetii. Repot argyroderma delaetii every 2–3 years into a snug pot of sandy, gritty mineral mix in a deep pot, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does argyroderma delaetii need?

When is the best time of year to repot argyroderma delaetii?

Should you water argyroderma delaetii after repotting?

No — not straight away. Repot argyroderma delaetii into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise argyroderma delaetii after repotting?

Not immediately. Wait about 3 weeks after repotting argyroderma delaetii. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.