Vegetable · Brassicaceae
Bok Choy
Brassica rapa subsp. chinensis
Sow it in cool weather, keep it watered and growing fast, and bok choy fills the bed in barely six weeks.
Full sun
Every 2–4 days
50–77°F · 10–25°C
40–55 days
Overview
Bok choy is a member of the cabbage family grown for its crisp stalks and tender leaves rather than a tight head. It comes together fast, going from seed to a full plant in 40 to 60 days, which makes it a favorite for filling a bed early in spring or late in fall. You can pick the outer leaves as you need them or cut the whole plant at the 10 to 15 leaf stage.
Cool weather is the whole game with this crop. It grows best between 50°F and 77°F (10°C to 25°C), and a cold snap in its first weeks or the heat and long days of summer will push it to bolt and turn bitter. Time your sowings for spring and fall and you sidestep most of that.
It asks little once it's growing. Give it steady moisture, fertile soil, and full sun, though it will still crop in partial shade, and you'll have crisp, mild greens for stir-fries and soups in a matter of weeks.
Care
The short version: full sun and cool weather, with steady moisture of about an inch of water a week, rich soil worked with compost, and quick harvest at the 10 to 15 leaf stage before heat sets it bolting.
Light
Bok choy wants full sun for the fastest, fullest growth, but it's flexible. It still makes usable heads on as little as 2 hours of direct sun a day, just more slowly, which makes it a fair pick for a part-shade bed.
Water
Keep the soil evenly moist with about 1 inch (2.5 cm) of water a week from rain or the hose, and more in sandy ground. Steady moisture is what keeps the stalks crisp and holds off bolting, so don't let the bed swing between bone dry and soaked.
Soil
Plant in fertile, well-drained soil that still holds some moisture, worked over with compost or well-rotted manure. A pH of 6.0 to 7.5 suits it, and nudging toward 7 helps where clubroot is a known problem.
Temperature
This is a cool-weather crop that runs best between 50°F and 77°F (10°C to 25°C). Cold below 50°F in the early weeks can trigger bolting, and summer heat pushes it to flower and turn bitter.
Humidity
Ordinary outdoor humidity is fine, so there's no number to hit. Watch instead for the warm, wet spells that ramp up pest and disease pressure, and give plants room for air to move.
Feeding
Work plenty of compost or well-rotted manure into the bed before planting and that carries most crops. On poor ground, a light nitrogen side-dress during growth keeps the leaves coming.
Pruning
There's no real pruning to do. Take the outer leaves as you need them or cut the whole head at the 10 to 15 leaf stage, and snap off any flower stalk the moment the plant starts to bolt.
Size & spacing
Plants stand 6 to 12 inches (15 to 30 cm) tall and about as wide. Thin dwarf types to roughly 12 inches apart and full-size plants a little more, giving each room to size up and stay airy.
When to plant
Bok choy is a cool-season crop that bolts in summer heat, so it grows in the shoulders of the year. Sow indoors a few weeks before the last spring frost or direct-sow around it, then sow again in midsummer for a fall harvest that matures as the weather cools.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 4-5 weeks before the last spring frost for an early crop
- Plant: Set transplants out around the last spring frost once hard freezes have passed; direct-sow in midsummer (July) for a fall crop that matures in cool weather
- Harvest: Harvest 40-60 days after seeding at the 10-15 leaf stage, before hot weather triggers bolting; spring and fall crops
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Most bok choy trouble shows up as chewed leaves, slime at the base, or a plant that suddenly runs to seed. Learn to read those signs early and you can step in before a crop is lost. Match what you see below, then act while it still helps.
Plants wilt and yellow even with enough water
When a plant wilts and yellows though the soil is moist, the trouble is at the roots. Clubroot swells and distorts them into useless clubs, while cabbage maggots tunnel through and chew them apart. There is no cure once clubroot takes hold, so pull and destroy infected plants and never compost them.
Fix:
- Remove and destroy infected plants; do not compost them
- There is no cure for clubroot in an infected plant
A tall flower stalk shoots up and leaf growth stops
This is bolting, and it usually follows a cold spell that tricks young plants into flowering, or the heat and long days of late spring. Once the stalk climbs, the plant pours its energy into seed instead of leaves. Cut the head before the buds open and you can still eat it, though it turns a touch bitter.
Fix:
- Harvest the head immediately, before the flowers open; it is still edible though it may be slightly bitter
Leaves peppered with tiny round shothole holes
Those pinprick holes are the work of flea beetles, tiny shiny black beetles that jump when you brush the plant and hit seedlings hardest. A floating row cover laid down at sowing keeps them off. Steady water and quick growth also let plants outrun the damage.
Fix:
- Cover plantings with floating row cover at seeding
- Keep plants growing fast with steady water so they outgrow damage
Ragged chewed holes with dark green droppings
Ragged holes and crumbs of dark frass point to cabbage caterpillars, including the imported cabbageworm, cabbage looper, and diamondback moth larvae. Check the leaf undersides where they hide and pick them off. For a bad run, spray Bacillus thuringiensis while the caterpillars are still small.
Fix:
- Handpick caterpillars
- Apply Bacillus thuringiensis (Bt) while caterpillars are small
Slime trails and holes low on the leaf stalks
Silvery trails and chewed stalk bases give away slugs and snails, which feed after dark in the damp, crowded base of the plant. Hunt them at night by hand or scatter iron phosphate bait around the plants. Clear away mulch and debris near the stems so they lose their daytime cover.
Fix:
- Handpick at night
- Use iron phosphate slug bait around plants
- Reduce mulch and debris immediately around stems
Toxicity
Bok choy is a kitchen vegetable through and through, safe for people and not listed as toxic to cats or dogs. The only real caveat is quantity, since the natural goitrogens common to all cabbages can cause gas or mild upset if any animal eats large raw amounts often. Horses are the one to watch, as extension guides flag brassicas as a poor fit for their diet.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Bok choy isn't on the ASPCA toxic list, so a nibble won't hurt a cat. A big plate of the raw leaves might bring on some gas or a mild upset stomach, nothing more.
Dogs None
Dogs can share a little cooked or raw bok choy without worry. The only catch is gas or loose stools if a dog wolfs down a large raw helping at once.
Horses None
NC State Extension flags this plant as one to keep out of a horse's diet, since brassicas don't sit well with equines in quantity. A stray leaf is harmless, but don't make a habit of feeding it.
Rabbits None
Rabbits handle small servings of the leafy greens fine. Introduce it slowly and keep portions modest, because too much rich brassica at once can leave a rabbit gassy.
Livestock None
Cattle, goats, and sheep can graze the leaves with no real danger. As with any brassica, a steady diet of nothing else can upset rumen digestion, so treat it as part of the mix rather than the whole meal.
Birds None
Backyard hens and other birds peck happily at the leaves and the bolted flowers. It's a wholesome green for them in moderation.
People Safe
Bok choy is grown to be eaten and is safe for the kitchen, raw in salads or cooked in a stir-fry. Only a steady habit of large raw amounts is worth a second thought, owing to the natural goitrogens shared across the cabbage family.
No special handling needed; safe to grow in household gardens.
Varieties
Bok choy comes in white-stemmed and green-stemmed forms and in full-size and baby types. These are the ones worth knowing by name.
Shanghai (green-stem) type
Called Shanghai Qing in China, it carries spoon-shaped leaves on pale green stalks rather than white ones and is often picked young as baby bok choy.
Dwarf types
These compact plants top out around 6 inches and can sit as close as 12 inches apart, maturing fast in a small space.
'Joi Choi'
A vigorous white-stemmed hybrid prized for its slow bolting and its ease with both cold and warm spells.
'Mei Qing Choi'
A green-stemmed baby pak choi hybrid that resists bolting well.
Companions
Bok choy grows best beside onions and aromatic herbs that throw pest-laying moths off the scent, and it shares a cool-season bed comfortably with beets.
Plant near
Onions: Extension companion-planting guides note onions get along well with all cabbage-family crops, and onion interplanting helped reduce cabbage looper and imported cabbageworm damage in brassica trials
Aromatic herbs (dill, sage, thyme, chamomile, rosemary): Cole crops do well planted with aromatic herbs; sage and thyme reduced diamondback moth pressure on brassicas in studies
Beets: Extension companion charts list beets as compatible neighbors for cabbage-family crops in the cool-season bed
How to propagate
Bok choy is grown from seed, and it's about as easy as seed sowing gets, with a fresh row ready to start every couple of weeks.
SeedEasy
Direct-sow or start indoors in early spring, and again in mid-to-late summer (around July) for a fall crop · Seed germinates in about 4-10 days in cool soil; plants reach transplant size in 3-4 weeks and harvest size in 40-60 days
Bok choy grows from seed and nothing else. Sow it a quarter to half an inch deep in early spring or again around July for a fall crop, and it sprouts in 4 to 10 days in cool soil. Thin to one plant every 6 to 12 inches by variety, and from there it's 3 to 4 weeks to transplant size and 40 to 60 days to a full head. Sow a fresh row every couple of weeks and you'll never run short.
Myths
Once bok choy starts to bolt, the plant is ruined and must be thrown out.
Catch it in time and a bolting plant is still good food. Cut the head before the flowers open and it eats much like a young one, just a little more bitter, and the flower stalks are tasty in their own right.
Bok choy needs full sun all day to make a crop.
Full sun grows the fastest, fullest heads, but the plant gets by on less. As little as 2 hours of direct sun a day still yields usable heads, just at a slower pace.