Mature size & growth rate

How big does Mustard Greens 'Red Giant' (Brassica juncea var. rugosa 'Red Giant') get?

Also called Red Giant mustard, red mustard greens.

More about mustard greens 'red giant'

About Mustard Greens 'Red Giant'

Brassica juncea var. rugosa 'Red Giant' · also called Red Giant mustard, red mustard greens · edible

Mustard greens 'Red Giant' is a vigorous Japanese mustard with large, savoyed purple-red leaves and a hot, peppery bite that mellows with cooking. Fast to crop at 40-45 days, it suits cut-and-come-again or full heads. A cool-season brassica, it grows best in spring and autumn; heat and long days drive it quickly to bolt.

Mature size: Leaves up to 30-45 cm long; plant about 30-45 cm tall and 30 cm wide at full size.

Indoor size vs how big it gets in the wild

Mustard Greens 'Red Giant' 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 leaves up to 30-45 cm long. In the ground with no restriction it is a completely different plant — plant about 30-45 cm tall and 30 cm wide at full size. — 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

Mustard Greens 'Red Giant' 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: feed for fast leafy growth: rich compost base plus a nitrogen side-dress 2-3 weeks after thinning. steady nitrogen keeps leaves tender and milder; avoid letting plants stall and toughen.

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

How to keep mustard greens 'red giant' smaller

You are not stuck with the maximum size. For mustard greens 'red giant' specifically, these are the levers, in order of impact:

Choose a compact or dwarf variety of mustard greens 'red giant' 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 mustard greens 'red giant' bigger or faster

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

When mustard greens 'red giant' outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for mustard greens 'red giant':

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 mustard greens 'red giant' repotting guide. If you want more of this plant instead of a bigger one, the mustard greens 'red giant' propagation guide turns prunings into new plants.

Mustard Greens 'Red Giant' size — frequently asked questions

How big does mustard greens 'red giant' get?

Mustard Greens 'Red Giant' reaches leaves up to 30-45 cm long when grown indoors, and far larger where it grows unrestricted (plant about 30-45 cm tall and 30 cm wide at full size.). 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 mustard greens 'red giant' slow or fast growing?

Mustard Greens 'Red Giant' is a fast grower. Expect a single growing season — it reaches full size in one year, then is done. Mustard Greens 'Red Giant' 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 mustard greens 'red giant' 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 mustard greens 'red giant' smaller?

Choose a compact or dwarf variety of mustard greens 'red giant' 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 mustard greens 'red giant' 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.