Green onion
Allium fistulosum
Also known asScallion · Spring onion · Salad onion · Bunching onion · Negi · Cebollin
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 3–10 (winter low around -40°C)
- Frost
- very hardy (survives deep cold)
- Season
- cool (spring/fall)
Growing systems
Root mass: light.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Soil-based mix (Potting soil) | varies | high | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Net pot, no medium (Bare-root) | - | - | - |
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 | 2 | 1 | 2 | 1.6 |
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
One of the easiest and fastest hydroponic crops. EC 1.0-2.0 mS/cm. pH 6.0-7.0. Temperature: 15–25°C (cool to moderate; tolerates a wide range). Moderate light (DLI 12-18 mol/m2/day). From seed to harvest: 6-8 weeks. From sets or bases: 2-3 weeks for usable greens. NFT, DWC, raft, Kratky, and vertical systems all work. The simplest hydroponic project: place store-bought green onion bases (with root nubs intact) in a jar of water on a windowsill; they regrow harvestable greens in 7-10 days. For continuous production, succession plant every 2 weeks. A. fistulosum varieties are perennial and regrow after cutting, providing indefinite harvests from a single planting. Harvest by cutting the green tops 3–5 cm above the base; the plant regrows from the center. For whole-plant harvest (white base and green top), pull the entire plant. Green onions are a staple crop for commercial hydroponic operations: fast turnover, consistent demand, good retail pricing ($2-4/bunch), and minimal pest or disease issues.