Mature size & growth rate

How big does Curly Kale (Brassica oleracea var. sabellica 'Curly Kale') get?

Also called curly kale, Scots kale, common kale.

More about curly kale

About Curly Kale

Brassica oleracea var. sabellica 'Curly Kale' · also called curly kale, Scots kale · edible

Curly kale is a hardy leafy brassica with tightly ruffled, frilly leaves on an upright stem. Exceptionally cold-tolerant, it crops through autumn and winter and actually sweetens after frost. Grow in full sun in firm, fertile, alkaline-leaning soil, keep it well watered and netted against cabbage pests, and pick young leaves over a long season.

Mature size: 40-60 cm tall, up to 90 cm if left to overwinter; 45-60 cm spread

Watch for — Aphids (cabbage aphid and whitefly): Grey-green aphid colonies cluster in the curled leaf folds and crowns, distorting growth. Blast off with water, encourage predators, and net or remove badly infested leaves.

Indoor size vs how big it gets in the wild

Curly Kale reaches its full size within one growing season — there is no "long-term" size, just how big it gets before you harvest or it dies back. Indoors and in a pot, expect 40-60 cm tall, up to 90 cm if left to overwinter. In the ground with no restriction it is a completely different plant — 45-60 cm spread — which is why the pot, the light and the pruning matter so much for the size you actually end up with.

It sizes up fast and once, racing from seedling to full size in a single season; after cropping it is finished, so size is a within-season question.

Growth rate and years to mature

Curly Kale is a fast grower. Realistically, expect a single growing season — it reaches full size in one year, then is done. Its feeding profile backs this up: a hungry crop. work compost or a balanced base feed into the bed, then side-dress with nitrogen-rich fertiliser once or twice during active growth to keep leaves coming. ease off feeding in late autumn so winter growth hardens off before hard frost.

Want this turned into the right next pot at the right moment? The pot size calculator and the curly kale repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast curly kale grows.

How to keep curly kale smaller

You are not stuck with the maximum size. For curly kale specifically, these are the levers, in order of impact:

Choose a compact or dwarf variety of curly kale from the start — that is the most reliable size control for an annual.
Grow it in a smaller container to naturally limit how large it gets.
For some crops, pinching or pruning the growing tips keeps the plant shorter and bushier.
Sow a little later or space plants closer if you specifically want smaller individual plants.

How to grow curly kale bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for curly kale the accelerators are:

Full sun, warm soil and steady water are what drive a crop to full size fastest.
Sow at the right time for your zone so it gets the whole season to size up.
Feed appropriately for the crop and never let it check (stall) from drought or cold.

Light is almost always the ceiling. The curly kale light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When curly kale outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for curly kale:

It sprawls beyond its bed or container before harvest — usually a spacing or support issue.
It flops or needs staking once it hits full height.
Once it has fruited or bolted, it is at its final size for good — the next plant is a new sowing.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the curly kale repotting guide. If you want more of this plant instead of a bigger one, the curly kale propagation guide turns prunings into new plants.

Curly Kale size — frequently asked questions

How big does curly kale get?

Curly Kale reaches 40-60 cm tall, up to 90 cm if left to overwinter when grown indoors, and far larger where it grows unrestricted (45-60 cm spread). It sizes up fast and once, racing from seedling to full size in a single season; after cropping it is finished, so size is a within-season question.

Is curly kale slow or fast growing?

Curly Kale is a fast grower. Expect a single growing season — it reaches full size in one year, then is done. Curly Kale reaches its full size within one growing season — there is no "long-term" size, just how big it gets before you harvest or it dies back.

How long does curly kale take to reach full size?

Roughly a single growing season — it reaches full size in one year, then is done. Light, pot size and feeding move that timeline more than anything else.

How do I keep curly kale smaller?

Choose a compact or dwarf variety of curly kale from the start — that is the most reliable size control for an annual. Grow it in a smaller container to naturally limit how large it gets. For some crops, pinching or pruning the growing tips keeps the plant shorter and bushier. Sow a little later or space plants closer if you specifically want smaller individual plants.

How can I make curly kale grow bigger or faster?

Full sun, warm soil and steady water are what drive a crop to full size fastest. Sow at the right time for your zone so it gets the whole season to size up. Feed appropriately for the crop and never let it check (stall) from drought or cold.