Growli
Let's go

Repotting guide

When & how to repot Red Cabbage (Brassica oleracea var. capitata f. rubra 'Red Drumhead')

Also called red cabbage, purple cabbage.

More about red cabbage

About Red Cabbage

Brassica oleracea var. capitata f. rubra 'Red Drumhead' · also called red cabbage, purple cabbage · edible

Red cabbage is a firm-headed cabbage with dense, deep-purple, anthocyanin-rich leaves storing well after harvest. It needs a long season in full sun and firm, fertile, alkaline-leaning soil with steady moisture. Net against cabbage pests, feed generously, and harvest the solid heads in autumn; many keep for weeks in cool storage.

Mature size: 30-45 cm tall and wide; heads 15-25 cm across, 1-2.5 kg

Watch for — Cabbage root fly: Root-feeding larvae wilt and kill transplants. Use brassica stem collars, net the bed against the egg-laying flies, and rotate brassicas year to year.

How to tell red cabbage needs repotting

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

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 red cabbage

Pot on seedlings as they grow; not a perennial repot. Red Cabbageis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Biennial grown as an annual; large outer leaves wrapping tightly into a solid, rounded, deep-purple head on a short stem..

What size pot to step red cabbage up to

Pot red cabbage 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 red cabbage

Pot red cabbage 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 red cabbage

  1. Pot on before it is root-bound. Check red cabbage regularly; move it up as soon as roots reach the edge of the cell or pot, not after they have circled.
  2. 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.
  3. 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.
  4. Pot into rich mix. Set it into fresh firm, fertile, well-drained soil, ph 6.5-7.5 at the same depth (tomatoes are the exception — they can go deeper to root along the stem).
  5. Water in and grow on. Water well, keep it in good light, and resume feeding once it is established and growing again.

Aftercare

Water red cabbage 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 red cabbage

Red Cabbage wants firm, fertile, well-drained soil, ph 6.5-7.5. Wants rich, deeply worked, firm ground on the alkaline side; lime acidic soils to suppress clubroot. Generous organic matter feeds the long-season crop, and firm planting anchors the heavy heads. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting red cabbage — frequently asked questions

How often should you repot red cabbage?

Pot on seedlings as they grow; not a perennial repot for red cabbage. Red Cabbage is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into firm, fertile, well-drained soil, ph 6.5-7.5 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 red cabbage need?

Pot red cabbage 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. Use our pot size calculator to size it from the plant's current pot and root spread.

When is the best time of year to repot red cabbage?

Pot red cabbage 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.

Can you put red cabbage straight into a much bigger pot?

No. Even a fast-growing red cabbage 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 red cabbage after repotting?

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

Related guides