Mature size & growth rate

How big does Choy Sum 'Sumo' (Brassica rapa var. parachinensis 'Sumo') get?

Also called Sumo choy sum, flowering pak choi.

More about choy sum 'sumo'

About Choy Sum 'Sumo'

Brassica rapa var. parachinensis 'Sumo' · also called Sumo choy sum, flowering pak choi · edible

Choy Sum 'Sumo' is a vigorous, large-framed flowering choy sum producing thick, succulent stems, broad leaves, and yellow buds for stir-fries. Bred for heavier yields and good heat tolerance, it matures in around 40-55 days and regrows side shoots after cutting, making it a productive cool- and warm-season Asian green.

Mature size: 35-50 cm tall and 25-35 cm wide.

Watch for — Flea beetles: Riddle seedling leaves with tiny holes, weakening young plants. Use fine mesh from sowing and feed for quick growth.

Indoor size vs how big it gets in the wild

Choy Sum 'Sumo' 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 35-50 cm tall and 25-35 cm wide.. 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

Choy Sum 'Sumo' 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 heavy feeder given its size: enrich soil with compost or balanced fertiliser before planting and apply nitrogen-rich liquid feed every 1-2 weeks during rapid growth for thick, tender stems.

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

How to keep choy sum 'sumo' smaller

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

Choose a compact or dwarf variety of choy sum 'sumo' 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 choy sum 'sumo' bigger or faster

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

When choy sum 'sumo' outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for choy sum 'sumo':

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

Choy Sum 'Sumo' size — frequently asked questions

How big does choy sum 'sumo' get?

Choy Sum 'Sumo' reaches 35-50 cm tall and 25-35 cm wide. 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 choy sum 'sumo' slow or fast growing?

Choy Sum 'Sumo' is a fast grower. Expect a single growing season — it reaches full size in one year, then is done. Choy Sum 'Sumo' 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 choy sum 'sumo' 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 choy sum 'sumo' smaller?

Choose a compact or dwarf variety of choy sum 'sumo' 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 choy sum 'sumo' 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.