Bok Choy Plant Profile

Bok Choy

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Bok choy used to be limited to meals in Chinese restaurants, but these days you are just as likely to find it growing in backyard gardens. It's a quick-growing vegetable with a surprising number of varieties to try.

Bok choy is a type of Chinese cabbage. Its Chinese name, "pak choi," translates to "white cabbage," probably because of its blanched centers, but there are green varieties too. The stalks are crisp and the leaves are smooth and tender with a flavor somewhere between cabbage and chard. Plants form an upright head, with outward flaring leaves, and its white or green stalks look like smooth, non-stringy celery. The stalk can shoot up to twice the size of the plant. Flower stalks grow from the center of the plant and have the yellow, 4-petal cross typical of the cruciferous family.

Botanical Name Brassica rapa var. chinensis
Common Name Bok choy, pak choi, bok choi
Plant Type Vegetable
Mature Size 10–24 inches
Sun Exposure Partial shade
Soil Type Rich, well-draining soil
Soil pH 6.5–7.0
Bloom Time Fall
Flower Color Yellow
Hardiness Zones 2–13
Native Area China

How to Grow Bok Choy

Bok choy is a biennial. Size will depend on the variety you are growing. In general, baby bok choy is less than 10 inches tall and standard bok choy varieties grow one to two feet tall, with a spread of about 12 inches.

You can succession plant every couple of weeks for a longer harvest period. Stop planting when the weather turns hot, then start new plants for the fall in mid-summer.

Light

Bok choy can handle full sun, but it grows best in partial shade. It needs about 3–5 hours of sun each day.

Soil

You'll need well-draining soil with a lot of rich, organic matter mixed in. Bok choy will grow in a soil pH from 6.0–7.5, although something in the 6.5–7.0 range is best.

Water

Bok choy needs consistent watering, especially in the fall. Drought can cause it to bolt to seed.

Temperature and Humidity

Bok choy grows in every hardiness zone in the United States. It does best in cooler weather; dry and hot conditions can cause bok choy to bolt prematurely. It is not as winter hardy as smaller leaved Asian greens, but it may survive under cover in USDA Hardiness Zones 4–7. However, it will quickly bolt to seed in the spring.

Fertilizer

Add compost and organic fertilizer to the soil when planting bok choy. These plants are heavy feeders, preferring soil that is rich in potassium, nitrogen, and phosphorus.

Growing from Seeds

You can direct sow or start seed indoors about four to five weeks before your last frost date. Begin sowing outdoors one to two weeks before your last frost date. Seeds are quick to germinate, usually within four to eight days. Hold off transplanting seedlings until nighttime temperatures remain above 50 degrees or be prepared to cover them. If they are exposed to frost or prolonged cold temperatures, they think they've been through a winter and start to bolt.

Plant seeds one-half inch deep, spaced one inch apart. Thin and eat the plants when they are a couple of inches tall. If you are growing full-sized plants, thin to at least a six-inch spacing.

Common Pests/Diseases

Bok choy is not usually affected by the most common brassica diseases. It is, however, attractive to many insect pests, including cabbage loopers and cabbage worms. Flea beetles can riddle the leaves. Row covers will help to minimize damage from all of these. Slugs, whiteflies, and aphids can also harm the leaves.

Harvesting

Depending on the variety and the weather, bok choy should be ready to harvest in 45–60 days. Slice the plants off about an inch above the ground and they should re-sprout for you. The plants will be smaller, but still delicious.

Bok choy is found in most grocery stores, and its uses go far beyond the usual stir fry. The tender young leaves can be eaten raw in salads or sandwiches. You can swap it for celery sticks, toss it in soups and stews, and even grill it. Bok choy can also be substituted for other cabbages

Varieties of Bok Choy

Although there are dozens of varieties of bok choy, many times you will find seed packets with no variety name. The small "baby" bok choys are popular in China and becoming more widely available elsewhere. You'll need more of them for a recipe, but they grow and mature very quickly.

  • 'Black Summer': Plant in fall and harvest into winter; very dark leaves
  • 'Ching-Chiang': Quick growing dwarf that can handle early spring weather
  • 'Joi Choi': A medium-sized plant with good bolt resistance
  • 'Mei Qing Choi': Dwarf variety that grows quickly (35 days)
  • 'Win-Win': Extra-large, dense heads; slow to bolt