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Entire healthy mature bok choy plant in a real garden bed, showing growth habit and scale.Primary identification image. 20–40 cm tall, 20–30 cm wide at maturity.

Bok choy

Brassica rapa subsp. chinensis (L.) Hanelt

Also called: Pak choi, Chinese cabbage (non-heading)

Family
Brassicaceae
Season
Cool-season annual
Best grown in
Portland, Oregon

A fast, juicy-stemmed Asian brassica for spring and especially autumn; heat and cold shocks make it bolt.

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Life cycle & growth stages

  1. 1. SeedSow 1 cm deep.
  2. 2. SeedlingEmerges in 4–7 days.
  3. 3. ThinningThin to 15–25 cm.
  4. 4. Mid-growthSpoon-shaped leaves with thick white stems.
  5. 5. Harvest readyHead 15–30 cm.
  6. 6. HarvestCut whole or pick outer stems.

Growth stages are ordered chronologically; timing varies with cultivar, temperature, light and care.

Planting calendar for Portland, Oregon

Start indoors 3–5 weeks before last frost; transplant 2 weeks before to 2 weeks after last frost; direct sow 3 weeks before to 2 weeks after last frost; 35–50 days to maturity from sowing. Windows are derived from the region's average frost dates (last Apr 5, first Nov 5) and are estimates until you confirm your own dates in the calendar.

Bok choyBrassica rapa subsp. chinensis
PlantStart indoorsDirect sowAutumn sowTransplantTendHarvest
Bok choyMar 1–Mar 15 (estimate)Mar 15–Apr 19 (estimate)Aug 27–Sep 24 (estimate)Mar 22–Apr 19 (estimate)—Apr 19–Jun 22 (estimate)
  • Start seeds indoors: Mar 1 – Mar 15
  • Direct sow: Mar 15 – Apr 19
  • Transplant outdoors: Mar 22 – Apr 19
  • Harvest: Apr 19 – Jun 22
  • Autumn sowing: Aug 27 – Sep 24

Spacing & support

In-row 15–25 cm; rows 30–30 cm. Planner footprint: 1 cell of 30 cm, 4 plants per cell.

Side-profile diagram of mature bok choy: canopy 20–40 cm tall, 20–30 cm wide, shallow root zone, support and harvest-access envelope.

Soil & water

Soil
Fertile, moist loam
pH
6–7
Fertility
high
Water
Constant moisture for crisp stems.
Frost
hardy; tolerates frost

Support & training

No support structure needed.

Bok choy mid-season before harvest, showing branching, vining, rosette or upright habit and space occupied.

Harvest signs

  • Heads 15–30 cm tall
  • Before the centre rises to flower
Bok choy at harvest readiness, showing the visual cues: heads 15–30 cm tall; before the centre rises to flower.

Common problems

Pests: flea beetles, slugs, cabbage white caterpillars

Diseases: clubroot

Appearance alone is not a diagnosis; confirm with a regional extension guide.

Side-by-side: healthy bok choy leaf or fruit and an example of clubroot.

Container growing

  • Minimum 5 L (15 cm deep)
  • Use quality potting mix and water more frequently
Mature bok choy in a correctly sized container (5 L or more) with drainage visible.

Companion overview

1 reviewed relationship record (evidence: low).

Supported or conditional

None reviewed

Avoid or separate

None with evidence

1 popular pairing reviewed with no verified relationship.

Full companion profile

Crop rotation

Avoid planting bok choy or other cabbage family crops in the same spot for 3 years. Rotation is about previous seasons, not about live neighbours.

Year 1Year 2Year 3BrassicaceaeOther familyOther familyback after 3+ years

Shared risks in Brassicaceae: clubroot, cabbage root fly, cabbage white caterpillars.

Crop rotation hub

Sources, reviewer & update

Sources

Reviewer: Garden Planner editorial team (pending independent horticultural review)

Last reviewed: August 15, 2026 · version 1

Found an error or have feedback? Let us know.

Growing bok choy

Bok choy matures in 35–50 days and can be harvested as baby leaves from three weeks. Spring sowings bolt easily after a cold snap, so autumn sowings are usually more reliable.

Bok choy seed beside a ruler or coin for scale.
Bok choy seedling at cotyledon and first-true-leaf stage, in soil, distinguishable from common weeds.
Bok choy mid-season before harvest, showing branching, vining, rosette or upright habit and space occupied.

Slugs, flea beetles and cabbage whites are the main pests. Space 15–25 cm apart depending on cultivar size, and keep well watered for crisp stems.

Two or more mature bok choy plants with a tape measure showing in-row spacing (15–25 cm).
Bok choy flower detail or bolting stage.
Immature leaves of bok choy developing on the plant.

Bok choy wants rich, moist soil and steady water; its thick white stems turn stringy in drought. Baby types can be spaced 15 cm apart and harvested whole at three to four weeks, while full-sized cultivars need 25 cm and six to seven weeks. Mesh cover from sowing keeps flea beetles and cabbage whites off, and a beer trap or evening patrol deals with slugs.

Edible parts and safety

Edible: leaves, stems.

Hands or tool harvesting bok choy correctly (cut, pull, twist or pick) without damaging the plant.

Pests and diseases

Common pests: flea beetles, slugs, cabbage white caterpillars. Common diseases: clubroot. These vary by region; a photograph is an example, not a diagnosis. See the pest and disease guides and your local extension service.

flea beetles on bok choy, with a wider damage-context view.

Timeline

Season timeline for bok choy: sowing, transplanting, flowering, harvest and bed occupancy aligned to frost dates.Text alternative: Start seeds indoors Mar 1–Mar 15; Direct sow Mar 15–Apr 19; Transplant outdoors Mar 22–Apr 19; Harvest Apr 19–Jun 22; Autumn sowing Aug 27–Sep 24.

Related plants

See also: Brassicaceae family page · crop rotation · regional calendar · guides

Our Methodology & Sources

We synthesize peer-reviewed research, university extension publications, and trusted horticulture resources. Our evidence levels help you understand how strong the science is behind the guidance.

Evidence tiers

Supported evidenceConsistent results from multiple robust studies
Traditional claimHistorical use reported, limited scientific support
Context dependentMixed or variable results across conditions
No verified relationshipNo reliable evidence identified

Primary source types

  • Peer-reviewed journal articles
  • University extension publications
  • Government & research institute reports
  • Systematic reviews & meta-analyses

Last updated

August 24, 2026

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