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Repotting guide

When & how to repot Scarlet Kale (Brassica oleracea var. sabellica 'Scarlet')

Also called Scarlet kale, red kale.

More about scarlet kale

About Scarlet Kale

Brassica oleracea var. sabellica 'Scarlet' · also called Scarlet kale, red kale · edible

'Scarlet' is a curly kale with finely frilled leaves that turn from green to vivid purple-red as cold weather sets in, making it both a winter vegetable and an ornamental. The colour deepens with frost and the leaves grow sweeter and more tender after a cold snap. It is a very hardy, heavy-feeding cool-season biennial grown as an annual, productive from autumn through winter.

Mature size: Typically 50-80 cm tall and 45-60 cm wide.

Watch for — Clubroot: Stunting and wilting with swollen, distorted roots in infected soil. Rotate brassicas, raise pH toward neutral with lime, and improve drainage; spores persist for years.

How to tell scarlet kale needs repotting

Repotting on a calendar is less reliable than reading the plant. For scarlet kale, 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 scarlet kale

Pot on seedlings as they grow; not a perennial repot. Scarlet Kaleis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Upright, non-heading biennial grown as an annual, forming a single stem with a crown of tightly curled leaves; harvest the lower leaves and it keeps cropping from the top..

What size pot to step scarlet kale up to

Pot scarlet kale 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 scarlet kale

Pot scarlet kale 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 scarlet kale

  1. Pot on before it is root-bound. Check scarlet kale 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 rich, firm, well-drained loam 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 scarlet kale 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 scarlet kale

Scarlet Kale wants rich, firm, well-drained loam. Fertile, organic-rich, moisture-retentive soil with a firm root run. Slightly acidic to neutral pH 6.0-7.5; lime toward neutral in brassica beds to limit clubroot. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting scarlet kale — frequently asked questions

How often should you repot scarlet kale?

Pot on seedlings as they grow; not a perennial repot for scarlet kale. Scarlet Kale 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 scarlet kale need?

Pot scarlet kale 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 scarlet kale?

Pot scarlet kale 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 scarlet kale straight into a much bigger pot?

No. Even a fast-growing scarlet kale 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 scarlet kale after repotting?

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

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