Repotting guide

When & how to repot Large-Flowered Kohleria (Kohleria grandiflora)

Also called Large-Flowered Kohleria, Kohleria.

More about large-flowered kohleria

About Large-Flowered Kohleria

Kohleria grandiflora · also called Large-Flowered Kohleria, Kohleria · flowering

A velvety-leaved Gesneriaceae from Colombia and Ecuador, Kohleria grandiflora produces tubular red flowers with yellow-spotted throats from spring through autumn. Grow it in bright indirect light with high humidity and consistently moist, well-drained soil. Rhizomes allow short dry spells but dislike cold. Near year-round blooms are possible under grow lights.

Mature size: 30–60 cm tall (12–24 in); spread 30–45 cm (12–18 in)

Watch for — Rhizome rot: Overwatering in winter or heavy, poorly draining compost causes rhizomes to rot. Reduce water sharply after stems die back and ensure the pot drains freely.

How to tell large-flowered kohleria needs repotting

Repotting on a calendar is less reliable than reading the plant. For large-flowered kohleria, 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 large-flowered kohleria) 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 large-flowered kohleria

Only every 2–4 years, when genuinely crowded. Large-Flowered Kohleria 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. Upright to slightly spreading rhizomatous subshrub with hairy, velvety stems and opposite leaves; dies back to rhizomes in winter..

What size pot to step large-flowered kohleria up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Large-Flowered Kohleria 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 large-flowered kohleria 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 large-flowered kohleria

Early spring, just as new growth restarts, is the ideal window for large-flowered kohleria. 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 large-flowered kohleria

Confirm it actually needs it. Slide large-flowered kohleria 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 large-flowered kohleria 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 peat-free, well-draining houseplant or african violet mix with added perlite, 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 large-flowered kohleria 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 large-flowered kohleria

Large-Flowered Kohleria wants peat-free, well-draining houseplant or african violet mix with added perlite. A light, slightly acidic mix (pH 5.8–6.5) with 20–30% perlite gives the drainage Kohleria rhizomes need. Heavy or compacted compost leads to crown 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 large-flowered kohleria — frequently asked questions

How often should you repot large-flowered kohleria?

Only every 2–4 years, when genuinely crowded for large-flowered kohleria. Only repot large-flowered kohleria 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 peat-free, well-draining houseplant or african violet mix with added perlite. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does large-flowered kohleria need?

When is the best time of year to repot large-flowered kohleria?

Does large-flowered kohleria like to be root-bound?

Yes — large-flowered kohleria 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 large-flowered kohleria after repotting?

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