Bok choy is the stir-fry green: crisp white stems and tender dark leaves, mild and sweet, ready in weeks and happy in weather that sends other greens to seed. It is one of the most useful vegetables in a small garden — fast, compact and versatile in the kitchen.
It takes 45–60 days to mature and it is hardy, so it is a spring and autumn crop. It is also the brassica that tolerates a little shade, which makes it the green for the bed that gets less sun than the rest.
Bok Choy at a glance
| Growing factor | What bok choy need |
|---|---|
| Sun | part shade |
| Soil pH | 6.0–7.5 |
| Days to germination | 7–10 |
| Days to maturity | 45–60 |
| Spacing | 8–12 inches |
| Water needs | moderate |
| Cold tolerance | hardy |
| Family | Brassicaceae |
Starting seeds
Bok Choy can be started indoors or sown direct, and either route works well. Indoors, sow in trays or cells and expect germination in 7–10 days; direct-sown seed goes into prepared soil once conditions are right for the crop. Starting indoors buys you a few weeks of season and gives steadier germination, while direct sowing is simpler and avoids transplant shock.
Choose the method that fits your season length: short-season gardens in Zones 3–5 gain the most from starting indoors, while Zones 8–10 can usually direct-sow with confidence. Our seed-starting calculator works out indoor sowing dates from your frost dates, and your local extension service can confirm what works in your area.
Bok choy can be started indoors or sown direct, with germination in 7–10 days. For a spring crop, start indoors in late winter in Zones 3–6, or direct-sow in spring in Zones 7–9; for the main crop, sow in late summer for autumn harvest — in Zones 6–8 sow in late summer, in Zones 9–10 in autumn, and in frost-free Zones 11–13 sow in the cool season. Sow in trays or direct, thinning to the final spacing once seedlings have a few true leaves. Sow little and often, since a big sowing matures all at once.
Transplanting and planting out
Set plants out 8–12 inches apart when they have three or four true leaves, handling them gently — bok choy roots dislike disturbance, so transplant on a cloudy day and water them in well. Give young transplants a little shade for the first few days until they settle. Bok choy grows fast, so do not leave seedlings in trays too long or they will bolt as soon as they are planted out.
When you set plants out, space them 8–12 inches apart — that spacing is what the mature plant needs, and crowding is one of the commonest causes of small harvests. Our plant-spacing calculator works out how many plants fit your bed, and the square-foot garden planner can lay the bed out for you. Harden seedlings off for a week before planting out, moving them outside for longer each day, and plant on a cloudy day or in the evening so they do not wilt in their first hours outdoors.
Soil and feeding
Bok choy wants fertile, moisture-retentive soil at pH 6.0–7.5, with plenty of compost dug in before planting. It is a quick, hungry crop, so a little balanced fertiliser at planting time helps, and a liquid feed halfway through the season keeps it growing fast. Like all brassicas, it should not follow another brassica in the same bed. A fine, crumbly soil gives the best growth — compacted soil stunts it.
Aim for a soil pH of 6.0–7.5 — a simple soil test will tell you where you stand, and garden lime or sulfur can nudge pH up or down over a season. Feed lightly and steadily rather than in one heavy dose: too much fast nitrogen late in the season pushes leafy growth at the expense of the part you eat. Our fertiliser calculator works out amounts for your bed size, and the raised-bed soil calculator and soil-volume calculator tell you how much mix a new bed needs. A mulch layer after planting keeps the soil moist and cool and feeds the soil as it breaks down.
Watering
Water needs are moderate: keep the soil evenly moist through the growing season, watering deeply when the top inch or two dries out. Deep, infrequent watering builds deeper roots than a daily sprinkle, and it keeps the plants steady through dry spells.
Water needs are moderate, but bok choy must not dry out — drought makes it bolt and turns the stems tough. Water little and often, keeping the soil moist, and mulch to hold moisture in. In hot weather, water in the morning and again in the evening if the plants wilt. A plant that wilts every afternoon is a plant that will bolt.
Water at the base of the plant, in the morning, so the leaves dry quickly and the water reaches the roots instead of evaporating off the surface. A soaker hose or drip line is ideal. Our watering calculator gives a starting point for your bed size and soil, and the watering schedule generator can build a routine around it. Mulch is your best friend here: a few inches of straw or shredded leaves cuts evaporation and keeps moisture even between waterings.
Sunlight and temperature
Bok choy is the one crop in this set that prefers part shade — it grows well with four to six hours of sun, and in hot climates afternoon shade is a blessing, keeping the leaves tender and slowing bolting. It is hardy, so light frosts do not hurt it, and a light frost can even sweeten the leaves. In Zones 8–10 it grows through winter; in frost-free Zones 11–13 grow it in the coolest months.
This crop is rated hardy for cold tolerance, so plan your season around that: hardy and frost-tolerant crops can be sown and harvested around frosts, while tender crops need warm soil and frost-free nights. Our sunlight calculator can check whether your spot gets enough sun through the season, and the hardiness-zone finder will confirm your zone. If your summers run very hot, afternoon shade or a shade cloth can keep a cool-season crop productive for a few extra weeks.
Pests and diseases
Bok choy attracts the usual brassica pests, and the tender leaves are a target for slugs. The ones to expect are cabbage worms, aphids, flea beetles and slugs.
- Cabbage Worms — green caterpillars that chew holes in leaves. Pick them off by hand and grow under fine mesh from planting day.
- Aphids — cluster in the growing point and on young leaves. Wash them off with water and encourage ladybirds.
- Flea Beetles — tiny beetles that pepper young leaves with shot-holes. Keep seedlings covered and watered — vigorous plants outgrow the damage.
- Slugs — chew holes in leaves and stems in damp weather. Pick them off at dusk and keep the base of the plant clear.
Inspect plants weekly, especially the undersides of leaves, and act early — a small problem caught in time is a hand-picked handful of pests, while a late one can cost the crop. Row cover keeps many flying pests off young plants, and healthy, well-watered plants resist attack far better than stressed ones. If you need help identifying what you are seeing, our pest-identifier helper and plant-disease checker walk through the symptoms.
Companion plants
Bok choy grows well with marigolds, basil, onions and lettuce. Lettuce and bok choy share a cool season and a bed happily, marigolds help keep soil pests down, and the part-shade tolerance of bok choy makes it a good crop for the shadier end of a bed. As a brassica, it should not follow another brassica in the same ground.
Good companions for bok choy include:
- Marigolds
- Basil
- Onions
- Lettuce
Our companion-planting finder can suggest more pairings for your bed plan. As a general rule, avoid planting members of the same family (Brassicaceae) in the same spot year after year — rotate beds so soil-borne problems do not build up.
Harvesting
Start picking outer leaves once the plant is big enough, from about 45 days after sowing, or cut the whole head when it reaches a good size — a sharp knife at the base, leaving the roots in the soil. Baby bok choy can be picked at half size, when the stems are at their sweetest. Pick before the plant bolts: once it flowers, the leaves turn tough and bitter. In a good autumn, a sowing gives you several weeks of picking.
Expect the crop to be ready about 45–60 days after sowing, though weather and variety shift that window by a week or two either way. Our harvest-date calculator works out your expected harvest date from your sowing date, and the vegetable-yield estimator can estimate how much a bed should produce. Harvest in the morning when plants are cool and crisp, and use a sharp knife or secateurs rather than tearing, which damages the plant and invites disease.
Common problems and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Bolting to seed | heat or transplant shock | Sow in cool weather; transplant young seedlings gently. |
| Tip burn on the leaves | calcium uptake upset by uneven watering | Water evenly and mulch. |
| Slugs eating the leaves | damp, still conditions | Pick slugs off at dusk; keep the bed clear. |
Bolting to seed
Likely cause: heat or transplant shock Bok choy bolts at the slightest stress — heat, drought, or a seedling left too long in a tray. Sow for the cool season, transplant while seedlings are young, keep the soil moist, and give afternoon shade in warm weather.
Tip burn on the leaves
Likely cause: calcium uptake upset by uneven watering Brown, papery edges on the inner leaves are tip burn, usually caused by uneven watering stopping the plant taking up calcium. Water evenly, mulch well, and the next leaves should be clean.
Slugs eating the leaves
Likely cause: damp, still conditions Slugs love the damp shade under bok choy leaves. Pick them off at dusk, keep the base of the plants clear of debris, and use traps in wet weather.
Frequently asked questions
When do I harvest bok choy?
From about 45 days after sowing — pick outer leaves as needed, or cut the whole head at the base. Baby bok choy can be picked at half size.
Why did my bok choy bolt?
Stress — usually heat, drought, or seedlings left too long in trays. Sow for the cool season, transplant young, keep the soil moist, and give afternoon shade.
Does bok choy need full sun?
No — it prefers part shade, which is unusual for a vegetable. Four to six hours of sun is enough, and afternoon shade in hot weather keeps the leaves tender.
Can I grow bok choy in a container?
Yes — it is ideal for pots. One plant per gallon of compost, kept well watered and out of the hottest sun.
What is tip burn on bok choy?
Brown, papery leaf edges, usually caused by uneven watering. Water evenly and mulch, and the next leaves should be clean.