Repotting guide

When & how to repot White Konjac (Amorphophallus albus)

Also called White Konjac, White Elephant Foot Yam.

More about white konjac

About White Konjac

Amorphophallus albus · also called White Konjac, White Elephant Foot Yam · edible

White Konjac is a Chinese edible aroid grown for its glucomannan-rich corm. It sends up a single mottled petiole with a large compound leaf each season, then dies back to dormancy. Thriving in dappled shade and humus-rich soil, it needs consistent moisture while growing and a dry rest period in winter. Tubers must be cooked before eating.

Mature size: Leaf canopy 60–120 cm tall and 60–90 cm wide; corms can reach 3–5 kg under ideal cultivation

Watch for — Corm rot (soft rot, white rot): The most serious threat in cultivation, caused by bacteria (Erwinia) or fungi in waterlogged or poorly drained soil. Ensure excellent drainage, avoid overhead watering, and inspect corms when repotting. Discard any soft or foul-smelling tissue.

How to tell white konjac needs repotting

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

Flowering has tailed off year on year and the clump has become congested and overcrowded.
Lots of leaf and few flowers — a classic sign that white konjac bulbs or tubers need lifting and dividing.
Bulbs visibly bursting the pot or pushing each other to the surface.
It is the natural dormancy window (foliage yellowed and died back) — the only safe time to lift and split.

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 white konjac

Lift and divide every 3–4 years once clumps congest. Rather than a true repot, white konjac is lifted and divided once the clump congests and flowering drops off. Tuberous geophyte; produces a single robust mottled petiole bearing a large compound palmate-pinnate leaf each season, followed by complete dormancy.

What size pot to step white konjac up to

Pot size matters less than depth and spacing here. When you replant white konjac, set the bulbs or tubers at the correct depth (a rough guide: two to three times their own height of soil over the top) and space them so they are not touching. A wide, shallow pot suits a clump better than a tall narrow one.

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 white konjac

The only safe window is dormancy: wait until the foliage has yellowed and died back naturally, lift and divide then, and replant before or at the start of the next growing season. Disturbing white konjac in full growth or flower sets it back badly.

Step-by-step: repotting white konjac

Wait for dormancy. Let white konjac foliage yellow and die back completely. Lifting while it is in growth wastes the energy it is storing for next year.
Lift carefully. Loosen the soil well away from the bulbs/tubers with a fork and ease the whole clump out without spearing them.
Separate the offsets. Gently pull the clump apart into individual bulbs or tubers. Keep only firm, healthy, blemish-free ones.
Replant at the right depth. Reset them in fresh rich, humus-heavy, well-draining loam at the correct depth and spacing — not touching — so each has room to bulk up.
Water in and rest. Water once to settle them, then keep on the dry side until growth resumes. Do not feed until leaves are actively growing.

Aftercare

After replanting white konjac, keep the soil barely moist — not wet — until shoots appear; bulbs and tubers rot in cold, saturated soil. Once leaves are growing strongly, resume normal watering. Hold off feeding until the plant is in active growth again.

The right soil mix for white konjac

White Konjac wants rich, humus-heavy, well-draining loam. Use a fertile mix of loam, leaf mold, and perlite (roughly 2:2:1). Excellent drainage is essential to prevent soft rot, a common problem in cultivation. Avoid heavy clay. Slightly acidic to neutral pH (6.0–7.0) suits this species. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting white konjac — frequently asked questions

How often should you repot white konjac?

Lift and divide every 3–4 years once clumps congest for white konjac. White Konjac is lifted and divided, not "repotted". Every 3–4 years, once the foliage has died back and it is dormant, lift the clump, separate the offsets, and replant at the correct depth in rich, humus-heavy, well-draining loam. Crowding, not pot size, is what reduces flowering over time.

What size pot does white konjac need?

When is the best time of year to repot white konjac?

Do you "repot" white konjac, or lift and divide it?

You lift and divide it. White Konjac grows from bulbs or tubers, so instead of repotting you wait for dormancy, lift the congested clump, separate the healthy offsets, and replant them at the right depth and spacing. Doing this every 3–4 years restores flowering.

Should you fertilise white konjac after repotting?

Hold off feeding white konjac until it is in active growth again. Fresh soil already carries enough nutrients to get it re-established, and feeding disturbed roots too soon does more harm than good.