Vegetableleafy greenStraightforward

Pak choi

Brassica rapa

A fast oriental brassica ready in about six weeks, and one that bolts almost on sight if sown before midsummer. Sown from July onwards as the days shorten it is one of the most productive autumn crops there is; sown in May it runs to flower and wastes the space.

Position: Full sun or Partial shade
Water: high demand
Drainage: Moisture-retentive
Grows to: 20–30 cm × 20–25 cm
Hardiness: H4
Harvest: August to November
Difficulty: Straightforward

August

Sow outdoors · Harvest

Pak choi’s year

Resolved for United Kingdom (general). Every window is stored against a climate event rather than a date, so a late frost pocket runs later than the band shows. What else August calls for.

Activity	J	F	M	A	M	J	J	A	S	O	N	D
Sow outdoors							July.	August.	September.
Harvest								August.	September.	October.	November.

Timing that travels

The band above resolves this plant's windows into months for one region. These are the windows themselves, stored against a climate event rather than a date — which is the form that survives being carried to a colder garden, a frost pocket, or next year.

Conditions it needs

Light: Full sun, Partial shade
Frost: Hardy
Hardiness rating: H4 (RHS)
Grows best at: 15–20 °C
Germinates at: 10–30 °C
Soil: Loam, Peat-free compost
Soil pH: 6–7.5
Drainage: Moisture-retentive
Water needs: high
Drought: poor tolerance
Waterlogging: moderate tolerance
Heat: poor tolerance
Wind and exposure: moderate tolerance

Where these figures come from

LightSourced guidancemoderate confidence

Royal Horticultural Society: Pak choi — position

Checked 2026-08-13

FrostSourced guidancehigh confidence

Royal Horticultural Society: Pak choi — hardiness

Checked 2026-08-13

Hardiness ratingSourced guidancemoderate confidence

Royal Horticultural Society: RHS hardiness ratings

Checked 2026-08-13

Grows best atSourced guidancemoderate confidence

Royal Horticultural Society: Pak choi — temperature

Checked 2026-08-13

Germinates atSourced guidancemoderate confidence

Royal Horticultural Society: Seed germination temperatures

Checked 2026-08-13

SoilSourced guidancemoderate confidence

Royal Horticultural Society: Pak choi — soil

Checked 2026-08-13

Soil pHSourced guidancemoderate confidence

Plant Finder — Missouri Botanical Garden: Brassica rapa — culture

Checked 2026-08-13

DrainageSourced guidancemoderate confidence

Royal Horticultural Society: Pak choi — soil

Checked 2026-08-13

Water needsHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

DroughtHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

WaterloggingHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

HeatHorticultural consensusmoderate confidence

Heat and long days both trigger bolting.

No external citation — see the evidence type above.

Checked 2026-08-13

Wind and exposureHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

On your soil

Computed by comparing this plant's recorded requirements against each soil's recorded characteristics. A recorded horticultural fact overrides the comparison where GrowingHQ holds one.

Soil	Verdict	Why
Heavy clay	Grows well here	Pak choi grows perfectly well on heavy clay without special measures, though it is not the soil it would choose.
Sandy	Works, with one condition	Pak choi will crop on sandy, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Chalky and alkaline	Works, with one condition	Pak choi will crop on chalky and alkaline, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Loam	Prefers this soil	Loam suits Pak choi as it stands: The pH suits it: it wants 6 to 7.5, and this soil is in that range. Loam is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering.
Silty	Grows well here	Pak choi grows perfectly well on silty without special measures, though it is not the soil it would choose.
Peaty and acid	Grows well here	Pak choi grows perfectly well on peaty and acid without special measures, though it is not the soil it would choose.
Shallow over rock	Works, with one condition	Pak choi will crop on shallow over rock, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Made ground and urban soil	Grows well here	Pak choi grows perfectly well on made ground and urban soil without special measures, though it is not the soil it would choose.

Not sure which you have? Four hand tests will settle it.

Space and spacing

Mature height: 20–30 cm
Mature spread: 20–25 cm
Rooting depth: 20 cm
Spacing: 20–25 cm apart

Where these figures come from

Mature heightHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Mature spreadHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Rooting depthHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
SpacingSourced guidancemoderate confidence: Royal Horticultural Society: Pak choi — spacing
Checked 2026-08-13

Measured centre to centre. Plants set closer than this compete for light and water long before they look crowded, and the crowding cannot be undone once they are in.

In a container

Minimum volume: 8 litres or more
Minimum depth: 20 cm

Where the container figures come from

Minimum volumeHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Minimum depthHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13

One of the best container crops there is — fast, shallow-rooted and cut young. Sow little and often rather than filling one pot, because it all matures at once.

Where and how you can grow it

Each way of growing is assessed separately, and “not assessed” is a real answer rather than a gap we have filled in with a guess.

Method	Suitability	What it needs
Open ground	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Traditional dug bed	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Raised bed	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Container	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13	8 litres; 20 cm deep
Greenhouse	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Polytunnel	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Cold frame	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Hydroponics	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13	A fast leafy crop with shallow roots — the profile that suits soilless growing best.
Windowsill	Workable source Horticultural consensusmoderate confidence Royal Horticultural Society: Growing herbs and salads indoors Checked 2026-08-13

Growing it

SowingSow from July onwards rather than in spring. Bolting is triggered by lengthening days as much as by heat, so a May sowing runs to flower whatever the weather does.
ProtectionNet against pigeons and cover with fleece in autumn. Pak choi grown into November under a cloche is one of the most productive things on a winter plot.
WateringPak choi runs to seed the moment it dries out, which is why so much of it bolts in its first fortnight. Keep the soil consistently moist and sow into ground that is already damp rather than watering after sowing.
FeedingA fast leafy crop grown on soil already enriched with compost needs no additional feed. Where it is being cut repeatedly, a liquid nitrogen feed after each cut keeps the regrowth coming.

Where this guidance comes from

SowingSourced guidancehigh confidence: Royal Horticultural Society: Pak choi — care
Checked 2026-08-13
ProtectionSourced guidancehigh confidence: Royal Horticultural Society: Pak choi — care
Checked 2026-08-13
WateringSourced guidancehigh confidence: Royal Horticultural Society: Pak choi — cultivation
Checked 2026-08-13
FeedingSourced guidancemoderate confidence: Royal Horticultural Society: Pak choi — cultivation
Checked 2026-08-13

Is it worth putting under cover?

Whether it will grow there is on the methods table above. This is whether the space is well spent, which is a different question and usually the one being asked.

Structure	What protection is worth	What decides it
Greenhouse	Extends the season source GrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13	Bolting and flea beetle. Pak choi bolts at the first check and is shredded by flea beetle outdoors; under cover in autumn it is a reliable crop.
Polytunnel	Extends the season source GrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13	Bolting and flea beetle.

On a windowsill

A few weeks, then replace

source

GrowingHQ editorial positionmoderate confidence

How long the crop is actually productive on an ordinary British windowsill without added light.

GrowingHQ editorial synthesis — GrowingHQ

Checked 2026-08-13

A supermarket pot or a sowing gives a few weeks of cutting and is then exhausted. That is what the crop is, not a failure to keep it alive. Bolting. A sowing gives two or three cuts of baby leaves and then runs to flower; that is the crop rather than a failure.

Harvesting

When it is readyCut the whole head at six to eight weeks, or take outer leaves and let the plant continue. Baby leaves are ready in as little as three weeks.
How to pick itCut the whole head through at the base with a knife, or take individual outer leaves and leave the centre to grow on — pak choi will regrow twice or three times from a cut stump if the cut is made cleanly about 3 cm above soil level. Harvest in the morning; the leaves wilt quickly once cut in heat.

Where the harvest guidance comes from

When it is readySourced guidancehigh confidence: Royal Horticultural Society: Pak choi — harvesting
Checked 2026-08-13
How to pick itSourced guidancehigh confidence: Royal Horticultural Society: Pak choi — harvesting
Checked 2026-08-13

Keep picking

Regular picking keeps this plant producing. Fruit or leaves left to mature signal it to slow down or stop.

What goes wrong

Problem	How often	Notes
Cabbage root fly	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	Transplants are the vulnerable stage; a collar or mesh at planting is the control.
Flea beetle	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13
Slugs and snails	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	The main pest by a distance.
Bolting	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	From long days as much as from heat, which is why the sowing window matters more than the weather.
Cabbage white caterpillars	occasional source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13
Clubroot	occasional source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13

Sources for this page

GrowingHQ editorial synthesis · Plant Finder · Royal Horticultural Society

Each figure on this page carries its own citation, under the “where these figures come from” note in its section. Record last reviewed 2026-08-14.

If something is wrong with it

Plant running up to flower before it is ready to eat — 2 causes GrowingHQ holds for pak choi

Something else? Work through it with the diagnostic tool.