Repotting guide

When & how to repot Geranium (pelargonium) (Pelargonium × hortorum)

Also called zonal geranium, bedding geranium, pelargonium.

About Geranium (pelargonium)

Pelargonium × hortorum · also called zonal geranium, bedding geranium · flowering

The plants sold in garden centres as "geraniums" are actually Pelargonium — tender South African shrubs grown for non-stop summer flowers. True hardy geraniums (cranesbills) are a different genus. Pelargoniums are drought-tolerant and easy in pots. Toxic to pets.

Garden 'geraniums' are Pelargonium species and hybrids, mostly native to South Africa; they are botanically distinct from the hardy temperate Geranium (cranesbill) genus.

Prefers light, free-draining soil or potting mix; heavy, wet ground readily rots the crown and roots.

Mature size: 30-60 cm tall

Sources: aspca.org, rhs.org.uk, rhs.org.uk

How to tell geranium (pelargonium) needs repotting

Repotting on a calendar is less reliable than reading the plant. For geranium (pelargonium), watch for these signs:

Roots poking out of the drainage holes or coiling visibly around the inside of the pot.
You are watering far more often than you used to because the rootball dries out within a day or two.
Water runs straight through and out the bottom without soaking in.
Top growth has slowed or new geranium (pelargonium) leaves are noticeably smaller than older ones despite good light.

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 geranium (pelargonium)

Every 12–18 months — sooner if roots show fast. Geranium (pelargonium)'s growth habit — tender perennial bush, often grown as an annual — sets the pace. The plants sold in garden centres as "geraniums" are actually Pelargonium — tender South African shrubs grown for non-stop summer flowers. True hardy geraniums (cranesbills) are a different genus. Pelargoniums are drought-tolerant and easy in pots. Toxic to pets.

What size pot to step geranium (pelargonium) up to

Step up one pot size — about 2–3 cm (an inch) wider. Geranium (pelargonium) grows fast, so it will fill that space within a season, but jumping several sizes at once still backfires: the unused soil stays soggy and rots even a vigorous root system. One size at a time, every year or so, is the rhythm.

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 geranium (pelargonium)

Early spring, just as new growth restarts, is the ideal window for geranium (pelargonium). 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 geranium (pelargonium)

Time it for spring. Repot geranium (pelargonium) in early spring as growth restarts so it re-roots quickly into the fresh soil.
Choose one size up. Pick a pot about 2–3 cm wider with drainage holes. One step only — a much bigger pot stays soggy and rots roots.
Ease the plant out. Water lightly the day before, then tip geranium (pelargonium) out and gently loosen any roots circling the bottom of the rootball.
Repot at the same depth. Put a layer of fresh free-draining potting compost in the new pot, set the plant so its soil line is unchanged, and backfill, firming lightly.
Water and pause feeding. Water once to settle the soil. Hold off fertiliser for about a month — fresh mix already has nutrients and feeding now burns new roots.

Aftercare

Water geranium (pelargonium) once to settle the soil, then let the surface dry before watering again — fresh mix around the roots stays wetter than the old compacted ball, so the commonest post-repot mistake is overwatering. Keep it out of direct sun for a week or two while roots re-establish. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for geranium (pelargonium)

Geranium (pelargonium) wants free-draining potting compost. Standard compost with 20% perlite; container culture suits them. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting geranium (pelargonium) — frequently asked questions

How often should you repot geranium (pelargonium)?

Every 12–18 months — sooner if roots show fast for geranium (pelargonium). Repot geranium (pelargonium) roughly every 12–18 months, in early spring as growth restarts. It grows fast and circles its pot quickly, so step up one size (about 2–3 cm wider) into fresh free-draining potting compost. Don't jump several sizes — that soggy excess soil is what rots vigorous roots.

What size pot does geranium (pelargonium) need?

When is the best time of year to repot geranium (pelargonium)?

Can you put geranium (pelargonium) straight into a much bigger pot?

No. Even a fast-growing geranium (pelargonium) should only go up one pot size at a time. A vastly oversized pot holds a reservoir of wet soil the roots cannot reach, which stays cold and soggy and rots the roots — the opposite of what you wanted.

Should you fertilise geranium (pelargonium) after repotting?

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