Leeks
Allium porrum
Also known asGarden leek · Allium ampeloprasum (broader species) · Poireau
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 5–10 (winter low around -29°C)
- Frost
- very hardy (survives deep cold)
- Season
- cool (spring/fall)
Growing systems
Root mass: moderate.
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 |
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 | 0.7 |
| vegetative | 2 | 1 | 3 | 1.8 |
Companion-growing notes
- Heavy uptake of potassium. 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 long-season but rewarding hydroponic crop. Deep media beds or large containers (15 cm depth for the root system, plus room for hilling/blanching). EC 1.5-2.5 mS/cm. pH 6.0-7.0. Temperature: 12–24°C (cool-season; tolerates light frost). Moderate light (DLI 12-18 mol/m2/day). Long season: 80-120 days from transplant depending on variety. Blanching is important for quality: as the plant grows, mound media, cardboard tubes, or opaque wraps around the shaft to keep it white. Without blanching, the shaft is green and tougher. Harvest when the shaft is 2–3 cm diameter. Baby leeks (harvested young at pencil thickness) are faster (50-60 days) and don't need blanching. The inevitable grit between leek layers (from mounding) requires thorough washing: slice the leek lengthwise and rinse each layer under running water. For commercial growers, baby leeks are more practical than full-sized because of the shorter crop time and premium pricing ($8-15/kg).