Mature size & growth rate

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

Also called Redbor kale, red curly kale, ornamental red kale.

More about redbor kale

About Redbor Kale

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

'Redbor' is a tightly curled F1 kale with striking deep magenta-purple, frilly leaves on a tall stem, equally at home in the vegetable plot and the ornamental border. The colour deepens and intensifies in cold weather, and the leaves sweeten after frost. Like all curly kales it is a hardy, heavy-feeding cool-season biennial, very frost-tolerant and at its best from autumn through winter.

Mature size: Typically 60-90 cm tall and 45-60 cm wide, occasionally taller when overwintered.

Watch for — Wind rock: Tall plants on loose soil rock in wind, loosening roots and stunting growth. Plant firmly and deeply, earth up the stem, and stake exposed plants.

Indoor size vs how big it gets in the wild

Redbor 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 typically 60-90 cm tall and 45-60 cm wide, occasionally taller when overwintered.. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

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

Redbor 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. enrich the bed with compost or aged manure before planting and side-dress or liquid-feed with a nitrogen-rich fertiliser every 3-4 weeks; steady feeding sustains the dense curly leaf production.

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

How to keep redbor kale smaller

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

Choose a compact or dwarf variety of redbor 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 redbor kale bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for redbor 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 redbor kale light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When redbor kale outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for redbor 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 redbor kale repotting guide. If you want more of this plant instead of a bigger one, the redbor kale propagation guide turns prunings into new plants.

Redbor Kale size — frequently asked questions

How big does redbor kale get?

Redbor Kale reaches typically 60-90 cm tall and 45-60 cm wide, occasionally taller when overwintered. when grown indoors. 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 redbor kale slow or fast growing?

Redbor Kale is a fast grower. Expect a single growing season — it reaches full size in one year, then is done. Redbor 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 redbor 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 redbor kale smaller?

Choose a compact or dwarf variety of redbor 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 redbor 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.