How to Grow Pak Choi
Brassica rapa subsp. chinensis
Pak choi is a fast-maturing Asian leaf vegetable ready to harvest in as little as 45 days. Grow it as a cool-season crop in spring or autumn, since heat and long days cause it to bolt quickly. Sow direct or transplant into fertile, moisture-retentive soil and cover immediately with fine insect mesh to protect against flea beetle. Keep soil consistently moist and harvest whole heads or outer leaves as needed.
When to Start
Sow indoors 6 weeks before last frost, or direct sow outdoors after frost risk has passed and soil reaches 8°C.
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Growth Stages
Approximate days from start
Care Essentials
- Incorporate well-rotted compost or a balanced granular fertiliser into the soil before sowing. Pak choi is a fast-growing crop and rarely needs additional feeding during its short growing cycle.
- Pak choi bolts quickly in heat or long days, so grow as a cool-season crop in spring or autumn. Cover immediately after sowing with fine insect mesh to protect against flea beetle — the biggest threat to this crop.
Growing Conditions
- Min. soil temperature
- 8°C+
- Germination temperature
- 15–25°C
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- Direct sow
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Spacing & Planting
| Plant spacing | 20 cm |
| Row spacing | 30 cm |
| Sow depth | 1 cm |
| Mature height | 30 cm |
| Mature spread | 25 cm |
Pests & Diseases
Pest Flea Beetle
Identification: Tiny round holes in seedling leaves; small shiny black beetles jumping when disturbed.
- Cover immediately with fine insect mesh — prevention is the only reliable control.
- Delay sowing until late summer when flea beetle populations are lower.
- Pyrethrin-based insecticide spray as a last resort on uncovered plants.
Pest Cabbage White Caterpillar
Identification: Ragged holes in outer leaves; green or yellow-striped caterpillars on leaf undersides.
- Hand-pick caterpillars and eggs from leaf undersides.
- Fine insect mesh keeps adults from laying eggs.
- Bacillus thuringiensis (Bt) biological spray targets caterpillars without harming other insects.
Pest Slugs
Identification: Irregular holes in leaves, often at night; silvery slime trails on soil and foliage.
- Scatter slug pellets containing ferric phosphate around young plants.
- Set beer traps sunk to soil level near the crop.
- Metaldehyde pellets (use sparingly and away from wildlife).
Disease Downy Mildew Peronospora brassicae
Symptoms: Yellow patches on upper leaf surface with grey-white fluffy growth on the underside.
Treatment: Remove and destroy affected leaves. Improve air circulation by thinning plants.
Prevention: Avoid overhead watering; grow under mesh which also reduces humidity around plants.
Disease Clubroot Plasmodiophora brassicae
Symptoms: Plants wilt in warm weather despite moist soil; swollen, distorted, club-shaped roots.
Treatment: No cure once established. Remove and destroy affected plants — do not compost.
Prevention: Lime soil to pH 7.0+, rotate brassicas on a strict 4-year cycle, and avoid importing infected soil.
Growing Conditions
| Min. soil temperature | 8°C |
| Germination temperature | 15–25°C |
| Base growth temperature | 5°C |
| Min. daylength to start | 10h |
| Photoperiod sensitivity | long day |
Frequently Asked Questions
- How far apart should I plant Pak Choi?
- Plant Pak Choi 20cm apart with 30cm between rows.
- Is Pak Choi frost hardy?
- Pak Choi is classified as Half Hardy.
