Broccoli rabe
Brassica rapa var. ruvo
Also known asRapini · Cime di rapa · Friarielli (Naples) · Italian broccoli · Choy sum (sometimes, loosely)
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: moderate.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Perlite (Expanded volcanic glass) | neutral / inert | very low | low |
| 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 | 2 | 1 | 1 | 1 |
| vegetative | 3 | 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
A fast, productive hydroponic crop for cool conditions. EC 1.5-2.5 mS/cm. pH 6.0-7.0. Temperature: 12–22°C (strictly cool-season; bolts immediately above 25°C, which is desirable since the flower buds are the harvest). Moderate light (DLI 12-18 mol/m2/day). From seed to harvest: 5-7 weeks, making it one of the fastest brassica crops. Harvest the central shoot with buds and 10–15 cm of stem when buds are tight and green, before any yellow flowers open. After the main shoot is cut, side shoots develop and provide additional harvests for 2-3 weeks. Works well in NFT, DWC, and media bed systems. The bitter, peppery flavor is valued in Italian and Asian cooking; blanching in salted boiling water for 1-2 minutes before sauteing reduces bitterness. For commercial hydroponic growers, broccoli rabe is a specialty crop that commands premium prices ($6-12/kg) in markets with Italian or East Asian demographics. Succession plant every 3 weeks for continuous supply. Pest-resistant compared to heading broccoli.
Notable varieties
| Cultivar | Type | Days | Notes |
|---|---|---|---|
| Sorrento | heirloom | 45 | Italian heirloom from the Sorrento area. Productive, classic rapini flavor, the variety most US seed catalogs offer as 'broccoli rabe.' |
| Quarantina | heirloom | 40 | 40-day Italian variety, very early. The variety for short spring windows or quick fall plantings. |
| Spring Rapini | open pollinated | 45 | Bolting-resistant selection bred for spring planting in warmer zones. Holds longer before flower stalks form. |