Bok choy
Brassica rapa subsp. chinensis
Also known asPak choi · Chinese cabbage · White cabbage · Pak choy · Buk choy · Bai cai · White cabbage (Chinese) · Chinese white cabbage
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 4–9 (winter low around -34°C)
- Frost
- tolerates light frost
- Season
- cool (spring/fall)
Growing systems
Root mass: light.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Rockwool (Mineral wool) | alkaline until pre-soaked | very high | low |
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Net pot, no medium (Bare-root) | - | - | - |
| Soil-based mix (Potting soil) | varies | high | high |
Nutrient demand by stage
NPK ratios are relative weights. EC targets shift through the plant's life.
| Stage | N | P | K | EC (mS/cm) |
|---|---|---|---|---|
| seedling | 1 | 1 | 1 | 0.8 |
| vegetative | 3 | 1 | 2 | 1.8 |
Companion-growing notes
- Heavy uptake of calcium. Co-grown crops with the same demand will end up deficient even at "correct" EC.
Aquaponics suitability
Compatible
Fish waste provides enough nitrogen for healthy growth. Supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.
Care notes
An excellent and fast-growing hydroponic crop, particularly suited to Asian vegetable production. EC 1.2-2.0 mS/cm. pH 5.5-7.0. Temperature: 15–24°C (cool-season crop; bolts quickly above 26°C). Moderate light (DLI 12-18 mol/m2/day). From seed to baby bok choy harvest: 3-4 weeks. Full-sized harvest: 6-8 weeks. Works perfectly in NFT, DWC, raft, and vertical systems. The compact rosette shape makes efficient use of growing space. Succession plant every 2-3 weeks for continuous harvest. In warm conditions, choose heat-tolerant varieties ('Mei Qing Choi', 'Win-Win') that resist bolting. Nutrient demand is moderate; standard leafy green formulation works. Flea beetles and caterpillars (cabbage loopers, diamondback moth) are the main pests in open greenhouse systems; row cover or BT (Bacillus thuringiensis) spray controls caterpillars. For commercial hydroponic growers, baby bok choy is a high-value crop ($6-12/kg) with fast turnover. In aquaponics, bok choy thrives in the nutrient-rich water and grows noticeably faster than in conventional hydroponics.