Mature size & growth rate

How big does Bok Choy 'Black Summer' (Brassica rapa var. chinensis 'Black Summer') get?

Also called Black Summer bok choy, dark bok choy.

More about bok choy 'black summer'

About Bok Choy 'Black Summer'

Brassica rapa var. chinensis 'Black Summer' · also called Black Summer bok choy, dark bok choy · edible

'Black Summer' is a fast, uniform bok choy with very dark green leaves and crisp pale stalks, bred for slow bolting and heat tolerance so it crops reliably through warmer weather. A cool-season Asian green, it matures in roughly six to eight weeks and is ideal for successional sowing in spring, summer, and autumn for stir-fries and steaming.

Mature size: About 20-30 cm (8-12 inches) tall and wide at harvest; baby leaves can be cut earlier.

Indoor size vs how big it gets in the wild

Bok Choy 'Black Summer' 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 about 20-30 cm (8-12 inches) tall and wide at harvest. In the ground with no restriction it is a completely different plant — baby leaves can be cut earlier. — 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

Bok Choy 'Black Summer' 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 leafy crop that responds to steady nitrogen. incorporate compost at sowing and side-dress or feed every 2-3 weeks with a balanced or nitrogen-leaning liquid feed for fast, tender growth.

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

How to keep bok choy 'black summer' smaller

You are not stuck with the maximum size. For bok choy 'black summer' specifically, these are the levers, in order of impact:

Choose a compact or dwarf variety of bok choy 'black summer' 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 bok choy 'black summer' bigger or faster

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

When bok choy 'black summer' outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for bok choy 'black summer':

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 bok choy 'black summer' repotting guide. If you want more of this plant instead of a bigger one, the bok choy 'black summer' propagation guide turns prunings into new plants.

Bok Choy 'Black Summer' size — frequently asked questions

How big does bok choy 'black summer' get?

Bok Choy 'Black Summer' reaches about 20-30 cm (8-12 inches) tall and wide at harvest when grown indoors, and far larger where it grows unrestricted (baby leaves can be cut earlier.). 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 bok choy 'black summer' slow or fast growing?

Bok Choy 'Black Summer' is a fast grower. Expect a single growing season — it reaches full size in one year, then is done. Bok Choy 'Black Summer' 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 bok choy 'black summer' 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 bok choy 'black summer' smaller?

Choose a compact or dwarf variety of bok choy 'black summer' 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 bok choy 'black summer' 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.