Pak Choi – Growing Guide

Overview

• Name: Pak Choi (also known as Bok Choy, Chinese White Cabbage, Mustard Cabbage)
• Botanical Name: Brassica rapa subsp. chinensis
• Plant Family: Brassicaceae
• Native to: China

Description

Pak Choi is a non-heading type of Chinese cabbage and a member of the mustard family. It is botanically a biennial plant but is almost always cultivated as an annual for its edible leaves and stalks. The plant typically forms a compact basal rosette and grows to a height of 20–40 cm (8–16 inches). Under certain conditions, particularly as days lengthen or temperatures rise, it may bolt (go to seed), producing an erect flowering stem that can reach up to 100 cm (39 inches).

The leaves are spoon-shaped, glossy, and green, with smooth surfaces and prominent veins. They are borne on thick, fleshy petioles (leaf stalks) that are usually white or pale green, giving the plant its characteristic vase-like appearance. These succulent stalks provide the crisp texture for which Pak Choi is valued. The root system consists of a central taproot with finer lateral roots that support rapid vegetative growth.

When bolting occurs, the plant produces clusters of small, bright yellow flowers, each with four petals typical of the Brassicaceae family. These are followed by slender seed pods that contain small, round seeds, completing the plant’s reproductive cycle.

Interesting Facts

1. Pak Choi has been cultivated since the 5th century in China, stretching back over 1,500 years, making it one of the oldest known vegetables in Asian agriculture. It thrives as a staple crop across Asia—from southern China to Japan, Korea, and Southeast Asia—where it was valued for its adaptability to diverse growing conditions.
2. The plant is self-fertile and pollinated by bees, contributing to its ease of cultivation. It is known for its rapid growth, with some varieties maturing in as little as 30 days.
3. Unlike napa cabbage, Pak Choi is a non-headed brassica that doesn’t form a compact head. Instead, its green leaf blades rise from lighter, bulbous stalks, forming an open rosette that resembles mustard greens—giving it the nickname “soup spoon” in Chinese.
4. Pak Choi is exceptionally nutrient-rich—offering high percentages of recommended daily vitamins A, C, and K, as well as calcium and folate, alongside modest amounts of B6 and potassium, with only around 13 kcal per 100 g.
5. As a member of the Brassicaceae family (which includes kale and broccoli), Pak Choi is rich in glucosinolates—compounds linked to anti-inflammatory and antioxidant activity, and potential protection against certain cancers.
6. Pak Choi’s mild, slightly peppery flavor and crunchy stalks make it a favorite worldwide—equally at home in stir-fries, soups, or eaten raw. It cooks quickly (leaves just 2–3 minutes), and is appreciated for its seamless blending into a variety of cuisines.

Basic Growing Information

Pak Choi is a cool-season crop that grows best in temperatures ranging from 15–20°C (59–68°F), though it can tolerate slightly warmer conditions up to 24°C (75°F) if moisture is sufficient. It thrives when grown in spring or autumn where conditions are milder, as hot weather above 25°C (77°F) often triggers bolting, causing plants to flower prematurely.

Pak Choi grows quickly, maturing in 30–60 days, making it suitable for succession planting to ensure a continuous harvest. In regions with hot summers, early spring and late summer plantings are recommended, while in mild climates, it can be grown nearly year-round. Frost-tolerant down to about –3°C (27°F), Pak Choi can be grown outdoors in cool climates or in containers for extended harvests. The plant prefers fertile, moist, and well-drained soil rich in organic matter, with consistent watering to maintain steady growth and prevent stress-related bolting.

• Sun Requirements: Full sun is ideal, but partial sun is tolerated, especially in warmer climates.
• Water Requirements: Medium to high – consistent soil moisture is needed to avoid stress.
• Soil Types and Properties: Fertile, loamy, and well-draining soils enriched with compost or organic matter. Avoid waterlogging.
• Soil pH: Slightly acidic to neutral, ideally between 6.0–7.5.
• Pot Size for Container Growing: At least 20–25 cm (8–10 in) deep and wide to allow for root development and adequate spacing.

Planting

Best Time to Plant:

• Climates with freezing winters: Plant in early spring, 2–4 weeks before the last frost, for a spring-to-summer crop; or in late summer to early autumn, approximately 6–8 weeks before the first frost, for a fall harvest.
• Climates with milder winters: Sow in late autumn to early winter, or continue planting through winter as long as daytime temperatures remain above about 10 °C (50 °F).

Note: Check gardening calendars for the best planting times in your location

• Spacing: Sow or transplant seedlings 15–30 cm (6–12 in) apart, depending on variety; with 30–45 cm (12–18 in) between rows for airflow and access.
• Seed Sowing Method: Sow seeds directly into the ground; or start in seed trays and transplant after the risk of frost has passed.
• Seed Sowing Depth: Sow seeds at a depth of approximately 0.5–1 cm (¼–½ in).
• Time to Harvest: Expect harvest readiness around 6–10 weeks after sowing, depending on the variety and growing conditions.
• Mature Height/Spread: Plants typically reach 30–60 cm (12–24 in) tall, with a spread of 15–30 cm (6–12 in), depending on whether it’s baby bok choy or full size.
• Grown From: Seeds

Care and Maintenance

• Watering Tips: Give pak choi consistent moisture—keep soil evenly and lightly moist, especially during summer heat when the plant is prone to bolting. Water at the soil base rather than overhead to prevent disease and promote healthy growth, allowing moisture to penetrate deeply into its shallow root zone.
• Fertilization: Work well-rotted compost or a balanced organic fertilizer into soil before planting. Once the plant is established, a light side-dressing of nitrogen-rich fertilizer can support rapid leafy growth—particularly in spring and fall crops—but avoid overfeeding, which may reduce flavor quality.
• Pruning: Pruning isn’t generally needed for pak choi. However, if the plant begins to bolt, removing flower stalks can prolong vegetative growth and delay seed formation for continued leaf harvest.
• Support: Pak choi typically holds itself upright and doesn’t need staking. In very windy sites or when leaves are very dense, planting in partial shade or wind-protected areas can prevent damage, avoiding the need for external supports.

Growing Difficulty

• Easy to Grow

Growing Tips

• Sow pak choi seeds every 2–3 weeks during spring or autumn to maintain a steady supply and prevent overwhelming bolting. Continuous planting ensures harvest windows remain open when earlier crops finish.
• In warmer climates, plant pak choi in partial shade—morning sun with afternoon shade—to help slow bolting and prolong leafy production during heat.
• Keep soil consistently moist, especially during warm spells, as moisture stress can trigger bolting. Apply mulch to retain moisture, suppress weeds, and moderate soil temperature for healthier growth.
• Use lightweight floating row covers or fine insect exclusion netting to shield young pak choi from flea beetles and other pests while simultaneously reducing temperature swings and improving early-season germination.
• Harvest pak choi when plants are 20–30 cm tall to ensure tender stems and leaves. For continuous harvests, remove outer leaves selectively, or cut the entire plant leaving roots to encourage a second flush.

Companion Plants

• Good companion plants include: Onions and garlic, whose strong scents help repel aphids and cabbage worms; chamomile and dill, which attract beneficial insects like hoverflies and parasitic wasps when in flower; and carrots and beets, which grow at different soil depths and reduce direct competition while encouraging beneficial soil organisms. Interplanting with legumes such as peas and beans can also be advantageous, as they fix atmospheric nitrogen and improve overall soil fertility, indirectly supporting leafy brassicas like pak choi.
• Avoid planting near: Other Brassicas such as cabbage, broccoli, cauliflower, kale, or mustard, as they share many of the same pests, including flea beetles, cabbage loopers, and root maggots, and are susceptible to the same soilborne diseases. Potatoes and tomatoes should also be avoided as neighbors, as they are heavy feeders that compete strongly for soil nutrients and may weaken the growth and yield of pak choi.

Common Pests and Diseases

Pests:

• Flea Beetles: These small, jumping beetles chew numerous small holes in leaves, often giving them a “shot-hole” appearance, which can severely weaken seedlings. Floating row covers provide effective prevention, and neem oil or insecticidal soap may reduce infestations. Crop rotation and removal of plant debris help limit populations.
• Aphids: These soft-bodied insects cluster on stems and leaf undersides, sucking sap and causing curling, stunting, and sticky honeydew deposits that encourage sooty mold. Control by washing off with a strong spray of water, introducing beneficial insects like lady beetles, or applying insecticidal soap or horticultural oil.
• Cabbage Worms and Loopers: Green caterpillars, including cabbageworm and cabbage looper, chew large holes in leaves and contaminate plants with frass. Handpicking, spraying with Bacillus thuringiensis (Bt) insecticide, and encouraging natural predators like parasitic wasps are effective controls. Floating row covers can prevent egg-laying by adult butterflies and moths.
• Diamondback Moth Larvae: Small green larvae that feed between leaf veins, leaving irregular holes and windowpane-like damage. Control measures include Bt applications, row covers, and crop rotation. Destroying crop residues also helps reduce overwintering pupae.
• Slugs and Snails: These pests feed at night and leave ragged holes in foliage and silvery slime trails. Use barriers such as copper strips, encourage natural predators, or handpick at night. Beer traps or organic slug baits can also be effective.

Diseases:

• Clubroot (Plasmodiophora brassicae): A soilborne disease causing swollen, distorted roots and stunted, yellowing plants. Prevention includes maintaining soil pH above 7.2 with lime, practicing long crop rotations (at least 7 years), and removing infected plant material to reduce inoculum.
• Downy Mildew (Peronospora parasitica): Appears as yellowish patches on upper leaf surfaces with gray-purple mold underneath. Control by improving air circulation, avoiding overhead irrigation, and rotating crops. Resistant cultivars and prompt removal of infected leaves help limit spread.
• Black Rot (Xanthomonas campestris pv. campestris): Bacterial disease that causes V-shaped yellow lesions starting at leaf edges, often leading to plant collapse. Prevention includes using certified disease-free seed, rotating crops for at least 3 years, and removing infected plants. Copper fungicide sprays may slow spread in early infections.
• Alternaria Leaf Spot (Alternaria brassicae, A. brassicicola): Characterized by dark circular spots with concentric rings, leading to leaf yellowing and drop. Management includes crop rotation, removal of plant debris, and application of appropriate fungicides if needed.
• Powdery Mildew (Erysiphe cruciferarum): Manifests as a white, powdery coating on leaves, reducing photosynthesis and vigor. Control with improved airflow, reduced humidity, and application of wettable sulfur or potassium bicarbonate sprays.

Harvesting

Harvest Time: Pak choi can be harvested at almost any stage of growth, from “baby bok choy” at around 30–35 days to mature heads at 45–60 days after sowing, depending on the variety and season. Leaves should be crisp and stems firm, with plants harvested before they bolt, as flowering causes the leaves to become bitter and tougher in texture.

Harvesting Tips: To harvest, use a sharp knife to cut the whole plant at the base just above soil level, or selectively harvest outer leaves and allow the inner rosette to keep producing for an extended period. Harvesting early in the morning when plants are fully hydrated will help maintain freshness and reduce postharvest wilting. Handle gently, as pak choi bruises easily and damaged tissue deteriorates more quickly.

Storage Tips: Remove any damaged or yellowing outer leaves, but avoid washing until ready to use, as excess moisture can encourage decay. Store unwashed pak choi in perforated plastic bags in the refrigerator at 0–5°C (32–41°F), where it will keep for about 1 to 2 weeks. For maximum shelf life, ensure high humidity (90–95%) to prevent leaf wilting. Quick use after harvest is recommended for best flavor and texture.

Propagation

• Produce New Plants From: Seeds

Culinary Uses

Pak choi is a cornerstone vegetable in many East and Southeast Asian cuisines, particularly in Chinese, Korean, and Japanese cooking, where it has been cultivated and consumed for centuries. Its appeal lies in the contrast between its crisp, juicy white stalks and tender, mild-flavored green leaves, which lend themselves to a wide range of preparations.

The most common method of cooking pak choi is stir-frying, often with garlic, ginger, soy sauce, and a splash of sesame oil. Quick cooking preserves its bright color and crunchy texture, making it a favorite side dish served with rice, noodles, or protein-rich mains. In Chinese hot pots, whole baby pak choi are blanched briefly in broth, where they absorb flavor while retaining their characteristic crunch.

Pak choi is also widely used in soups and noodle dishes. In Chinese wonton soup, Korean kimchi jjigae, or Japanese ramen, it contributes both bulk and freshness, balancing the richness of broths and meats. Steaming or braising whole heads of pak choi brings out its subtle sweetness, while grilling or roasting at high heat develops a slightly smoky, caramelized flavor. Young, tender leaves can even be eaten raw, making a nutritious addition to salads or used as a garnish.

Flavor-wise, pak choi pairs particularly well with soy sauce, oyster sauce, sesame, chili, garlic, and ginger, as well as with proteins such as tofu, chicken, pork, and seafood. Its versatility makes it equally suitable for light, health-focused dishes or more robust, savory meals.

Nutritionally, pak choi is a nutritious leafy green, supplying vitamins A, C, and K, folate, calcium, and other essential minerals, while being low in calories. Its mild taste makes it an easy way to incorporate more greens into the diet without overpowering other ingredients.

In short, pak choi’s combination of culinary versatility, appealing texture, and nutritional value has secured its place as one of the most important and widely used Asian leafy vegetables, now increasingly appreciated in kitchens around the world.

References

• Brassica rapa Chinensis Group (Bok Choy, Chinese White Cabbage, Field Mustard, Mustard Cabbage, Pak Choi) | North Carolina Extension Gardener Plant Toolbox. (n.d.). https://plants.ces.ncsu.edu/plants/brassica-rapa-chinensis-group/
• Cabbage, Chinese. (2019, October 1). College of Agricultural Sciences. https://horticulture.oregonstate.edu/oregon-vegetables/cabbage-chinese
• Chinese cabbage | Diseases and Pests, Description, Uses, Propagation. (n.d.). https://plantvillage.psu.edu/topics/chinese-cabbage/infos
• Growing Chinese cabbage and bok choy in home gardens. (n.d.). UMN Extension. https://extension.umn.edu/vegetables/growing-chinese-cabbage-and-bok-choy
• Liu, G. (2023, February 10). Bok choy, an Asian leafy green vegetable emerging in Florida. Ask IFAS – Powered by EDIS. https://edis.ifas.ufl.edu/publication/HS1337
• University of Guam. (2018, February). Growing bok choy (Brassica rapa Chinensis Group) varieties for Guam (FPP-07). College of Natural & Applied Sciences, University of Guam Cooperative Extension & Outreach. https://www.uog.edu/_resources/files/wptrc/BokChoy.pdf
• University of Arkansas System Division of Agriculture Cooperative Extension Service. (2011). Fennel (Home Gardening Series: FSA-6083). Arkansas Cooperative Extension Bulletin. https://www.uaex.uada.edu/publications/PDF/FSA-6066.pdf