Brassica rapa Chinensis Group (Bok Choy)

Bok Choy (Brassica rapa Chinensis Group), also known as Pak Choi, is one of the two main types of Chinese cabbage. It is prized for its crunchy stalks surrounded by glossy, emerald leaves and its mild flavor reminiscent of cabbage or spinach. A popular ingredient in Asian cuisine, this cool-season vegetable is quick and easy to grow in the home garden.

What is Bok Choy?

• Bok Choy belongs to the Brassicaceae or cabbage family, which includes broccoli, cabbage, cauliflower, radishes, and horseradish.
• Native to China, this subspecies of Brassica rapa is also known as Chinese White Cabbage, Field Mustard, Mustard Cabbage, or Pak Choi.
• Regarded as one of the oldest cultivated vegetables in the world, Bok Choy has been grown since the 5th century in Asia. Today, it is produced in many countries around the world.
• This annual to biennial cruciferous vegetable has an upright habit and forms a tight clump of waxy, green leaves, 8-10 in long (20-25 cm), with prominent white veins, loosely clustered to a bulbous base.
• The flower stalks have the yellow, four-petal cross typical of the cruciferous family.
• Fast-growing, the plant can reach 6-24 inches in height (15-60 cm) and 6-18 inches in spread (15-45 cm).
• Both the leaves and thick stems are edible.
• Bok Choy is winter-hardy and tolerates light frost.
• Rich in nutrients but low in calories, this Chinese cabbage provides many health benefits. Add it to your diet and enjoy it in fresh salads and savory dishes.

Bok Choy versus Napa Cabbage

Bok Choy should not be confused with the other subspecies, Brassica rapa Pekinensis Group, known as Napa Cabbage, Celery Cabbage, Chinese Cabbage, or Peking Cabbage. While these two vegetables look alike and even share common names, they are slightly different.

• Bok Choy is slightly larger, with thick white stalks and spoon-shaped, dark green leaves. Napa cabbage features densely packed, large and elongated heads of crinkly pale green leaves.
• Bok Choy has a much stronger taste and takes longer to cook than Napa cabbage.
• Bok Choy is more cold tolerant (USDA Zones 2-11) than Napa cabbage (USDA Zones 4-7).
• Finally, Bok Choy is typically ready to be harvested 45-60 days after planting, while Napa needs 70-90 days to reach maturity.

Bok Choy Health Benefits

• While Bok Choy makes a flavorful addition to many dishes, it also provides health benefits.
• Bok Choy is low in saturated fat and cholesterol and contains vitamins, minerals, and nutrients.
• Vitamin C: one cup of raw Bok Choy contains 35% of your daily needs. Vitamin C serves many essential roles in the body, helps make collagen, and boosts your immune system.
• Vitamin K: one cup contains 26% of your daily needs. Vitamin K is critical for blood clotting.
• Vitamin A: one cup contains 17% of your daily needs. This vitamin is essential for your eyes, immune system, heart, and kidneys.
• Bok Choy contains folate, a B vitamin that helps lower the risk of birth defects and is also important for reducing depression.
• It is also a good source of fiber, protein, and phosphorus and an excellent source of potassium and manganese.
• It also contains powerful antioxidants, which fight harmful free radicals and inflammation.
• Boy Choy promotes bone structure and strength thanks to its content of iron, phosphorous, calcium, magnesium, zinc, and vitamin K.
• Calcium, potassium, and magnesium in Bok Choy can help naturally lower blood pressure.
• Some studies suggest that Bok Choy could lower the risk of developing lung, prostate, and colon cancer.
• Please note that this vegetable contains compounds related to aspirin (salicylates). If you are sensitive to aspirin, you should consult your doctor.
• Nutrition Facts (one cup or 70g): 9 calories, 1.5 grams carbs, 1.05 grams protein, 0 grams fat, 0.7 grams fiber.

Cooking with Bok Choy

• Bok Choy is most commonly eaten as a fresh leafy vegetable in salads and the famous Korean kimchi dish. It has a crisp, chewy texture with a sweet and mustard-like flavor.
• It can also be steamed, boiled, grilled, braised, and sautéed.
• It develops a tender texture when cooked, and the flavor mellows to a taste similar to spinach and cabbage.
• A key ingredient in Asian cuisine, it can be chopped and stuffed into dumplings or fresh spring rolls, added into soups, mixed into noodle dishes, or lightly stir-fried and served as a side dish.
• It is traditionally eaten during Chinese New Year celebrations and is believed to represent good luck, prosperity, and blessings of a long life for elders.
• The leaves and stems can be kept for one week when stored in a plastic bag in the refrigerator’s crisper drawer.

Growing Bok Choy

• Bok Choy grows up to 6-24 inches tall (15-60 cm) and 6-18 inches wide (15-45 cm), depending on the variety.
• It performs best in full sun to partial shade in organically rich, consistently moist, well-drained soils with a pH between 6.0-7.5.
• Prepare the soil in advance by adding well-rotted manure or garden compost.
• Depending on the variety, Bok Choy takes 25-70 days to harvest.
• Bok Choy is a cool-season crop that can withstand light frost. It grows best in temperatures between 55-70°F (13-21°C).
• You can grow Bok Choy from seed or nursery seedlings.
• Sow seeds about ¼ inch deep (½ cm) and ½ inch apart (1 cm) in early spring (after the danger of frost has passed) for a spring and early summer harvest.
• Sow seeds in mid to late summer for a fall crop.
• Bok Choy can be grown in containers of a minimum size of 1 gallon and depth of 20 in (50 cm).
• Sow every three weeks for successive crops and a more extended harvest period.
• If sown during the summer, Bok Choy may bolt (flower), although this may be prevented by consistent watering and harvesting of the plants when young.
• Thin seedlings 8-20 in apart (20-50 cm), depending on the variety.
• When growing multiple rows, space the rows about 18 to 30 inches apart (35-75 cm) for best results.
• Keep the soil weed free.
• Mulch to retain moisture and control weeds.
• Like Cabbage, Bok Choy is a heavy feeder susceptible to nutrient deficiencies, including boron, calcium, phosphorus, and potassium.
• Make sure you add compost and organic fertilizer to the soil before planting.
• Practice crop rotation: To avoid diseases and pests that persist in the soil, do not plant Bok Choy where members of the cabbage family (broccoli, cauliflower, brussels sprouts, or kale) have grown for at least 3 years.
• Bok Choy is propagated by seed.

Harvesting and Storing

• Bok Choy is usually harvested within 5-8 weeks after germination, although Baby Bok Choy varieties can be harvested within 5 weeks after germination when they are no taller than 10 inches (25 cm).
• It can be picked at various stages, from young to mature, either one leaf at a time for a continuous supply or the whole head at once.
• When harvesting the entire Bok Choy plant, cut the whole head at ground level as a one-time harvest.
• Alternatively, Bok Choy leaves can be harvested several times from individual plants as ‘cut and come again’ salad leaves.
• Harvest the older outer leaves by cutting them off about 1 inch (2.5 cm) above the soil level. This allows the younger new leaves to grow and form new heads for future harvests.
• After harvesting and cleaning, Bok Choy is best stored at 32°F (0°C) at 95-100 percent relative humidity for up to three (3) weeks.

Pests and Diseases

Bok Choy is a host for a wide range of pests and diseases.

• Pests: Keep an eye out for aphids, cabbage aphids, cabbage root maggot, cabbageworms, cutworms, diamondback moths, flea beetles, grasshoppers, harlequin bugs, slugs, and snails. Row covers may help prevent insect and frost damage.
• Diseases: Brassica Alternaria, leaf spot, Brassica Black Rot, Brassica Downy Mildew, and Cabbage Soft Rot.

Companion Planting

Since Boy Choy belongs to the same family as cabbage (Brassicaceae), it likes and dislikes the same plants.

• Excellent companion plants are Agastache, Beets, Borage, Calendula, Celery, Chamomile, Cabbage, Collards, Dill, Garlic, Lavender, Mustard, Nasturtium, Onions, Oregano, Potatoes, Rosemary, Sage, Southernwood, Sweet Alyssum, Tansy, Thyme, Wormwood.
• Agastache helps repel the white cabbage butterfly.
• Borage is said to deter tomato hornworms and cabbage worms and is also one of the best plants for attracting bees and wasps.
• Calendula is a trap crop that will attract any aphids the beneficial insects miss and give the pests a more enticing meal than the brassicas and lettuce.
• Celery improves Bok Choy’s health and growth and helps repel the white cabbage butterfly.
• Chamomile has a strong aromatic scent and is an excellent companion plant for cabbage plants as it can improve their vigor and flavor. Another benefit is that the plant is host to hoverflies and wasps.
• Clover interspersed with cabbage plants can decrease the prevalence of cabbage worms and cabbage aphids by increasing the population of predatory ground beetles.
• Dill improves Bok Choy’s health and growth. It also attracts hoverflies, lacewings, ladybugs, and parasitic wasps, which will help control the aphids and cabbage worms.
• Garlic planted near cabbage plants repels insects with its odor.
• The strong scent of lavender will mask the smell of cabbage plants and confuse pests like aphids.
• Nasturtiums deter insect pests such as the infamous beetles and aphids.
• Onions are beneficial because they will repel rabbits from your cabbage plants.
• Aromatic plants, including peppermint, and rosemary, help repel cabbage flies.
• Sage repels cabbage moths and black flea beetles. If allowed to flower, it will also attract many beneficial insects – And the flowers are lovely.
• Tansy deters cabbage worms and cutworms.
• Thyme deters cabbage worms and helps repel the white cabbage butterfly.
• Southernwood, and wormwood help repel the white cabbage butterfly.
• Sweet alyssum will attract hoverflies, lacewings, ladybugs, and parasitic wasps, which will help control the aphids and cabbage worms.

• Do not plant Bok Choy near Corn, Eggplants, Grapes, Lettuce, Peppers, Pole Beans, Rue, Strawberries, or Tomatoes.