Bok Choy care — light, water, toxicity and hardiness
Bok Choy (Brassica rapa subsp. chinensis) wants partial shade and a drink about every 2 days once established. It is grown as an annual, so hardiness zones do not gate it.
| scientific name | Brassica rapa subsp. chinensis |
|---|---|
| family | Brassicaceae |
| category | vegetable |
| plant type | annual |
| light | partial shade |
| water cadence days | 2 |
| mature height cm | 30 |
| frost tolerant | true |
| edible | true |
How often should I water Bok Choy?
Fast and cool-season; bolts in heat.
Is Bok Choy toxic?
We do not have a verified toxicity record for this species, so we will not say either way. Treat it as unknown around pets and children until a vet or a poison-control source says otherwise.
Who eats it
Palatable to browsing animals such as deer: high. Palatable to grazing animals: high. Palatable to people: yes.
What it needs
Its shade tolerance is medium. Its moisture use is high. Its drought tolerance is low. It wants at least about 35 inches of rain a year. Above roughly 55 inches of annual rain it struggles. It tolerates soil down to pH 5.0. It tolerates soil up to pH 8.0. Its fertility requirement is high. Adapted to coarse, sandy soils: yes. Adapted to medium, loamy soils: yes. Adapted to fine, clay soils: yes. It needs at least 125 frost-free days. Its salt tolerance is medium. Its tolerance of chalky soil is high. Its fire tolerance is low. Fire resistant: no. It has been recorded down to -13°F. It suppresses neighbours chemically: no.
How it grows
It grows as a single crown form. Its growth rate is rapid. It puts on most of its growth in spring, summer, fall. It spreads by seed at a moderate rate. It resprouts after damage: no. Coppices: no. At maturity it reaches about 3.0 feet. Its roots go down at least 12 inches. Its shape is erect. It holds its leaves through winter: no.
What it looks like
It blooms in late spring. Conspicuous in flower: no. The foliage is green. The foliage texture is coarse. In summer the canopy is dense in porosity. In winter it is porous in porosity. Fall colour: no. The fruit or seed is brown. Fruit begins in summer. Fruit finishes by summer. It fruits high. The fruit persists on the plant: no. The fruit is conspicuous: no.
Growing more of it
Propagated by seed: yes. Propagated by cuttings: no. Propagated by container: no. Propagated by bare root: no. Propagated by bulb: no. Propagated by corm: no. Propagated by tubers: no. Cold stratification required: no. Seedling vigour is high. Commercial availability: routinely available.
Source: Drafted from US Cooperative Extension horticulture guidance; pending HUMAN-05 review (issue 280) · 2026-09-02