Bok choy has a plethora of names and spellings, including pak choi, bok choi, pak choy, Chinese mustard, Chinese cabbage, and spoon cabbage. This green is commonly eaten raw when young and steamed or sautéed when a bit older. The leaves have a mild, sweet flavor that resembles that of Swiss chard. Bok choy is relatively easy to grow in temperate climates, but note that it will not survive hard frosts and tends to bolt if grown in hot summer conditions. A relative of the turnip, it was originally grown in China, with cultivation and breeding focusing on leaves instead of roots. If left in the ground for a second season, it will sprout yellow flowers.
Unlike other varieties of bok choy, Purple Choi has a lovely purple hue with a green center instead of the standard all-green leaves. This plant has a sweeter flavor than many other varieties, which makes it great for salad mixes and stir-fries. At full maturity, Purple Choi reaches approximately 6–8″ in height; however, it’s especially tender in its earlier stages and can be harvested as early as 20 days into growth when the plant is only 2–3″ tall.
Seed Depth: 1/4–1/2″
Space Between Plants: 6″
Space Between Rows: 18″
Germination Soil Temperature: 45–75°F
Days for Germination: 5–10
Sow Indoors: 8–10 weeks before average last frost date.
Sow Outdoors: 4–6 weeks before average last frost date. For fall crop, plant again in late summer, 2–3 months before average first frost date. In areas with warm winters, plant in fall for a winter crop.
Grows best in cool, mild weather. More likely to bolt if exposed to frost or excessive summer heat. In most areas, they are best grown as a spring or fall crop. If your winters don’t drop much below freezing, plant in the fall to harvest greens throughout the winter.
Natural: Full sun.
Artificial: Grows best under fluorescent lights. Needs at least 7 hours of light daily. Take note: excess light will not help production but actually stress out your plants. And stress just doesn’t taste good.
Soil: Prefers well-drained loamy soil with high amounts of organic matter. A pH of between 6.5 and 7.0 will keep plants healthy and nourished.
Soilless: Start seeds in a soilless mix or using mineral wool.
Hydroponics: Thrives in a variety of hydroponic systems, including NFT, media-based drip systems, and deep water culture.
Aeroponics: Thrives in aeroponic systems.
Water: Requires moderate levels of water. Soil must be kept consistently moist for best growth and tastiest leaves.
Nutrients: Requires moderate to high levels of nutrients to support its fast growth. Add a source of organic matter such as compost or aged manure before planting.
Foliar: Will benefit from a foliar feeding of compost tea when young.
Pruning: If you plant the seeds densely, thin to 6″ apart and eat the thinnings as baby greens.
Mulching: Use mulch to moderate soil temperatures, which will help to keep plants from bolting.
Rotation: A 2- to 3-year rotation away from all plants in the brassica family is recommended.
Companions: Grows well with potatoes, beets, celery, and onions. Nasturtiums and aromatic herbs planted nearby will help repel insects and slugs. Avoid tomatoes and strawberries.
Harvest: You can eat bok choy as a microgreen by sprouting seeds in a seed tray and cutting them down about 7–10 days after they begin to sprout. You’ll know they’re ready when the first set of true leaves has developed. For baby bok choy, cut the entire plant at the soil level once it has reached 4–6″ in height. You can harvest mature outer leaves individually, allowing the plant to continue growing from the center and prolonging your harvest time. When the flower stalk begins to form and the plant is 6–8″ tall, cut the whole plant before the leaves get bitter.
Storage: Mature leaves will keep well loosely wrapped in a plastic bag in the refrigerator. Try to use them within two weeks from harvesting. Younger plants, microgreens, and sprouts will perish more quickly, so use those within 3–5 days.
Fun Fact: This plant in many ways resembles some of the more commonly recognized plants in the US such as collard greens and broccoli. Although bok choy didn’t make it to the US until the mid to late 1800s, it’s actually distantly related to these plants, which accounts for its similar appearance.
Preserve: Although bok choy may be frozen, it’s not recommended. Leaves may also be dried as is commonly done in Chinese households. To dry, blanch leaves and pat dry. Place on a baking sheet and in the oven at 200°F for up to 12 hours, turning leaves every couple hours. Leaves may also be preserved or pickled.
Prepare: As the stems are somewhat tough compared to the leaves, it’s easiest to blanch the bok choy before cooking. If you are searing the greens, make sure they are dry before adding to the pan as wet leaves will cause them to steam.
Nutritional: Contains high levels of vitamin(s) C, K, A, B6, B5, and B1. Also contains trace amounts of various minerals such as calcium, iron, phosphorous, magnesium, manganese, and potassium.
Medicinal: Because of its high vitamin content and low calories, bok choy can be a positive addition to any diet. As it also possesses many helpful antioxidants, it has been speculated that it can assist in preventing certain types of cancer such as breast and colon. Bok choy has also been linked to lowering levels of “bad” cholesterol.
Warnings: As with most other vegetables, eating bok choy in normal amounts is perfectly safe and can actually improve one’s health. If eaten in excess, however, bok choy can cause hypothyroidism—a condition in which the thyroid ceases to release adequate amounts of the hormone that regulates your metabolism.
Although commonly associated with Chinese cuisine, bok choy is also a lovely addition to the Korean dish called Kimchi. Store your Purple Choi Kimchi in clear glass jars so you can enjoy the beautiful variety of colors as well as the delicious flavors!