Pak Choi
Brassica rapa var. chinensis
Pak choi is a fast-growing Asian brassica with crisp, succulent stems and tender leaves harvested in 4-8 weeks. It is prone to bolting in warm weather, so spring and autumn sowings are most reliable. It can be harvested as whole heads or as baby leaf, and the mild, slightly mustard flavour suits stir-fries, soups, and salads.
Key facts
- Family
- Brassicaceae (Brassicas)
- Category
- Leafy
- Sowing window
- Mar–May, Aug–SepNow
- Sowing depth
- 10 mm
- Watering
- medium
- Frost sensitivity
- medium
- Days to maturity
- 30-60 days
- Harvest window
- May - Nov
Sowing notes
- -Avoid June-July sowings - heat triggers rapid bolting
- -Spring and late summer are the most reliable sowing windows
- -Succession sow every 3-4 weeks
Varieties
Canton Dwarf is a compact, fast-maturing pak choi ideal for small spaces and container growing. It produces dense, dark-green rosettes of crisp stems and tender leaves, ready to harvest in around 30-40 days. Less prone to bolting than larger types and well suited to spring and autumn sowings.
Joi Choi is a popular F1 pak choi producing large, upright heads with thick white stems and dark green leaves. It is one of the most bolt-resistant pak choi varieties, making it more reliable across the growing season than open-pollinated types. Excellent flavour whether stir-fried, steamed, or eaten raw.
Issues & threats
Wilting
EnvironmentalPlants are drooping or losing vigour. Most commonly caused by water stress but can also indicate root damage, vascular disease, or heat scorch. Identifying the cause quickly is important as some causes are serious.
Poor germination
EnvironmentalSeeds are emerging unevenly or not at all. Usually caused by soil temperature being too low, seeds sown too deep, poor seed-to-soil contact, or old seed stock.
Damping off
Fungal diseasePythium spp. / Phytophthora spp.
Young seedlings collapse at or just below soil level, caused by fungal pathogens that thrive in overwatered, poorly ventilated growing conditions. Can spread rapidly through a seed tray.
Yellowing leaves
EnvironmentalLeaves are turning yellow, which can indicate a range of problems including nutrient deficiency, overwatering, disease, or natural senescence. Identifying whether the pattern is upper or lower leaves, whole leaves or between veins, is key to diagnosis.
Stunted growth
EnvironmentalPlants are significantly smaller or slower to develop than expected. May be caused by poor soil, nutrient deficiency, root restriction, compaction, pest damage to roots, or disease.
Clubroot
Fungal diseasePlasmodiophora brassicae
A severe soil-borne disease causing grotesque swelling and distortion of brassica roots. Infected plants cannot take up water or nutrients effectively and typically collapse or die back. Spores survive in soil for up to 20 years. One of the most serious diseases affecting the brassica family.
Chewing damage
PestGeneral chewing damage from an unidentified pest, leaving holes or missing leaf sections. May be caused by caterpillars, beetles, or other insects. Inspect at dusk to identify the culprit.
Sap-sucking pests
PestGeneral sap-feeding pest activity causing weakened or distorted growth. May be caused by aphids, whitefly, scale insects, or other sucking insects. Inspect leaf undersides and growing tips to identify the pest.