Gai lan
Brassica oleracea var. alboglabra
Also known asChinese broccoli · Kai lan · Chinese kale · Jie lan
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 4–10 (winter low around -34°C)
- Frost
- tolerates light frost
- Season
- cool (spring/fall)
Growing systems
Root mass: moderate.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| 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 | 2 |
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
A fast, productive hydroponic crop well-suited to Asian vegetable production. EC 1.5-2.5 mS/cm. pH 6.0-7.0. Temperature: 15–25°C (cool to moderate; tolerates heat better than regular broccoli but bolts faster above 28°C). Moderate light (DLI 14-20 mol/m2/day). NFT, DWC, or media bed systems work. From seed to harvest: 5-7 weeks for baby gai lan, 7-10 weeks for full-sized stems. Harvest the main stem with 2-3 leaves when the first flower buds appear but before they open (open flowers indicate overmaturity and tougher stems). After the main stem is cut, side shoots develop and provide 2-3 additional harvests. The thick stem should be peeled if the outer layer is fibrous (split the base; if it's stringy, peel). Caterpillars and aphids are common brassica pests; BT spray and careful monitoring manage them. For commercial hydroponic growers near Chinese communities, gai lan is a consistent seller with strong demand. Succession plant every 2-3 weeks for continuous supply.