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. Hold EC around 1.4-2.0 mS/cm and pH 6.0-7.0. It is strictly cool-season, best at 12–22°C; above about 25°C it bolts at once, which is actually fine since the flower buds are the harvest. Keep light moderate, 14-22 mol/m2/day. From seed to harvest is only five to seven weeks, among the fastest of the brassicas. Cut the central shoot with its tight green buds and 10–15 cm of stem before any yellow flowers open; side shoots then develop for another two to three weeks of picking. It does well in NFT, deep water culture and media beds. A one to two minute blanch in salted boiling water before sauteing softens the bitterness. It is a premium specialty crop in markets with Italian or East Asian demand, more pest-resistant than heading broccoli, and worth succession-sowing every three weeks for a steady supply.
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. |