Repotting guide

When & how to repot Kai-lan (Gai Lan) (Brassica oleracea var. alboglabra)

Also called kai-lan, gai lan, Chinese broccoli, Chinese kale.

More about kai-lan (gai lan)

About Kai-lan (Gai Lan)

Brassica oleracea var. alboglabra · also called kai-lan, gai lan · edible

Kai-lan, or Chinese broccoli, is a Brassica oleracea grown for thick, sweet flowering stems, blue-green leaves, and small white-budded heads. Harvested before full bloom in roughly 50-70 days, it has a robust broccoli-like flavour, tolerates heat better than heading broccoli, and resprouts side shoots after the main stem is cut.

Mature size: 30-50 cm tall and 25-40 cm wide.

Watch for — Clubroot: Swollen, distorted roots and stunting in infected brassica soils. Rotate crops, lime to near-neutral pH, and improve drainage.

How to tell kai-lan (gai lan) needs repotting

Repotting on a calendar is less reliable than reading the plant. For kai-lan (gai lan), 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 kai-lan (gai lan) 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 kai-lan (gai lan)

Pot on seedlings as they grow; not a perennial repot. Kai-lan (Gai Lan)is grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Upright, leafy plant producing a thick central flowering stem with white buds; cutting the main stem encourages tender lateral shoots for repeat harvests..

What size pot to step kai-lan (gai lan) up to

Pot kai-lan (gai lan) 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 kai-lan (gai lan)

Pot kai-lan (gai lan) 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 kai-lan (gai lan)

Pot on before it is root-bound. Check kai-lan (gai lan) 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 rich, firm, well-drained loam 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 kai-lan (gai lan) 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 kai-lan (gai lan)

Kai-lan (Gai Lan) wants rich, firm, well-drained loam. Fertile, organic-rich soil, pH 6.0-7.5, ideally firmed for steady brassica growth. Lime acidic soils toward neutral to suppress clubroot. Grows in large, deep 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 kai-lan (gai lan) — frequently asked questions

How often should you repot kai-lan (gai lan)?

Pot on seedlings as they grow; not a perennial repot for kai-lan (gai lan). Kai-lan (Gai Lan) is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into rich, firm, well-drained loam 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 kai-lan (gai lan) need?

When is the best time of year to repot kai-lan (gai lan)?

Can you put kai-lan (gai lan) straight into a much bigger pot?

No. Even a fast-growing kai-lan (gai lan) 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 kai-lan (gai lan) after repotting?

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