Repotting guide

When & how to repot Kumquat Nagami (Citrus japonica 'Nagami')

Also called Nagami kumquat, oval kumquat.

More about kumquat nagami

About Kumquat Nagami

Citrus japonica 'Nagami' · also called Nagami kumquat, oval kumquat · edible

The most widely grown kumquat, bearing small oval orange fruit eaten whole, skin and all: the rind is sweet while the flesh is tart. 'Nagami' is a compact, slow-growing, very ornamental citrus that is among the cold-hardiest, fruiting in winter. Its neat habit and tolerance of cooler conditions make it ideal for pots and small gardens.

Mature size: About 2-3 m (6-10 ft) in the ground; easily kept to under 1-1.5 m (3-5 ft) in a pot.

How to tell kumquat nagami needs repotting

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

Roots circling the bottom of the module or pot, or poking out of the drainage holes.
The seedling dries out within a day and growth has visibly stalled.
Roots are white and matted in a tight spiral when you tip the plant out.
It has outgrown its current container for the stage of the season — pot kumquat nagami on before it becomes hard root-bound.

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 kumquat nagami

Pot on seedlings as they grow; not a perennial repot. Kumquat Nagamiis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Small, dense, slow-growing evergreen shrub or compact tree with fine twiggy branches, small glossy leaves and a tidy, naturally bushy form that lends itself to containers and bonsai..

What size pot to step kumquat nagami up to

Pot kumquat nagami on gradually — a seedling jumped straight into a huge pot sits in cold, wet, airless soil and stalls. Step up one or two sizes at a time as the roots fill each container, finishing in a large final pot or the ground. The aim is roots that never circle and never check.

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 kumquat nagami

Pot kumquat nagami on through the active growing season, whenever roots fill the current container — there is no single date, just "before it becomes root-bound". Avoid potting on during a cold snap.

Step-by-step: repotting kumquat nagami

Pot on before it is root-bound. Check kumquat nagami regularly; move it up as soon as roots reach the edge of the cell or pot, not after they have circled.
Step up one or two sizes. Choose the next container up — not a giant one. Cold, wet, unused soil around a small root system stalls seedlings.
Knock it out gently. Support the stem, tip the pot, and ease the rootball out without breaking it. A little teasing of circled roots at the base is fine.
Pot into rich mix. Set it into fresh well-draining, slightly acidic citrus mix at the same depth (tomatoes are the exception — they can go deeper to root along the stem).
Water in and grow on. Water well, keep it in good light, and resume feeding once it is established and growing again.

Aftercare

Water kumquat nagami in well and keep it in bright light; a freshly potted-on seedling can wilt for a day while roots settle, so do not overcompensate by drowning it. Do not fertilise for about 1 week — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for kumquat nagami

Kumquat Nagami wants well-draining, slightly acidic citrus mix. Loam-based or specialist citrus compost with grit for drainage, ideally pH 6.0-6.5. As with all citrus, sharp drainage is essential to prevent root rot in containers. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting kumquat nagami — frequently asked questions

How often should you repot kumquat nagami?

Pot on seedlings as they grow; not a perennial repot for kumquat nagami. Kumquat Nagami is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into well-draining, slightly acidic citrus mix so the roots never circle the cell, ending in a large final container. A root-bound transplant stalls and never fully recovers.

What size pot does kumquat nagami need?

When is the best time of year to repot kumquat nagami?

Can you put kumquat nagami straight into a much bigger pot?

No. Even a fast-growing kumquat nagami 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 kumquat nagami after repotting?

Not immediately. Wait about 1 week after repotting kumquat nagami. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.