Napa cabbage
Brassica rapa subsp. pekinensis
Also known asChinese cabbage · Wong bok · Wombok · Pe-tsai · Hakusai · Baechu · Celery cabbage · Michihili (cylindrical type)
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 4–9 (winter low around -34°C)
- Frost
- frost hardy
- Season
- cool (spring/fall)
Growing systems
Root mass: moderate.
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 nitrogen, 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
A cool-season hydroponic crop for Asian vegetable production. Grow in large containers or media beds with about 15 cm depth. EC 1.5-2.2 mS/cm. pH 6.0-7.0. Temperature: 13–21°C (critical: above 24°C the head fails to form and the plant bolts; prolonged cold below 10°C also triggers bolting in some varieties). Moderate light (DLI 14-18 mol/m2/day). From transplant to head harvest: roughly 60-90 days depending on variety. Harvest when the head is firm and dense; squeeze the top gently to check. Tipburn (internal browning of leaf margins) is a quality problem in some conditions, so keep calcium adequate and airflow good. Mini napa varieties ('Little Jade', 'Minuet') form smaller heads faster and suit space-limited systems. For growers near Korean or Chinese communities napa is a staple with steady demand, and the autumn kimjang season brings a seasonal spike.
Notable varieties
| Cultivar | Type | Days | Notes |
|---|---|---|---|
| Bilko F1 | hybrid | 60 | Slow-bolting hybrid with high resistance to clubroot and fusarium yellows. The most forgiving napa for hot or variable climates, holds firm 1-foot heads even when picked early. The variety to start with if you've failed at napa before. |
| Michihili | open pollinated | 70 | Tall cylindrical-head type, the original Chihli selection refined by Ferry-Morse. Less heat-tolerant than modern hybrids but the traditional choice for Asian markets. Heads can reach 18 inches tall with a tapered top. |
| Wong Bok | open pollinated | 75 | Squat barrel-shaped heads, the classic supermarket napa shape. Mild sweet flavor, stores well in the fridge for weeks once cut. More bolt-prone than Bilko, plant for fall harvest. |
| Minuet F1 | hybrid | 55 | Johnny's Selections-vetted Korean hybrid (2000). Small dense heads, useful for cramped spaces or short shoulder seasons. Slower to bolt than the heirlooms; sized for one or two meals rather than a kimchi batch. |
| Blues F1 | hybrid | 65 | Bolt-tolerant pekinensis hybrid often grown as a spring crop where most napa would flower. Slightly looser head than Bilko but more uniform across a transplanted block. Common in commercial CSA production. |