Celeriac
Apium graveolens var. rapaceum
Also known asCelery root · Knob celery · Turnip-rooted celery · Apium rapaceum · Céleri-rave
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 3–9 (winter low around -40°C)
- Frost
- frost hardy
- Season
- cool (spring/fall)
Growing systems
Root mass: heavy. Thin-channel systems can't hold this crop.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Soil-based mix (Potting soil) | varies | high | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
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 | 2 | 1.7 |
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, moderate-difficulty hydroponic root crop. Requires deep growing medium (20 cm) in media beds or large containers. EC 1.5-2.5 mS/cm. pH 6.0-7.0. Temperature: 15–22°C (cool-season crop; bolts in sustained heat above 25°C). Moderate light (DLI 12-18 mol/m2/day). The growing season is long: 100-120 days from transplant. Start seeds indoors 10-12 weeks before the target transplant date because germination is slow (2-3 weeks) and seedling growth is initially very slow. The root swells at the soil surface level; do not bury it. Remove lower side roots and leaves during development to encourage a smooth, compact root. Consistent moisture is critical; drought stress causes the root to become hollow, pithy, and crack. Boron deficiency causes brown, corky spots inside the root. Harvest when roots are 8–12 cm diameter. The stalks and leaves are edible and useful for flavoring soups and stocks (stronger celery flavor than the root). For European-style cooking, celeriac is a worthwhile investment of garden space despite the long season.
Notable varieties
| Cultivar | Type | Days | Notes |
|---|---|---|---|
| Brilliant | open pollinated | 110 | Earlier-maturing German cultivar. White-fleshed root with smoother skin than most celeriac, less prone to internal browning. Good choice for shorter-season climates. Stores well. |
| Giant Prague | heirloom | 120 | Late-1800s Czech heirloom, the classic kitchen-garden celeriac. Larger roots than modern cultivars, slightly more knobby. Excellent flavor, the variety chefs reach for. Heat-tolerant relative to other celeriacs. |
| Mars | hybrid | 130 | Modern F1 with smoother skin and resistance to internal browning. Reliable production for commercial growers and home gardens with consistent moisture. Stores 6+ months in cool conditions. |