Broccoli
Brassica oleracea var. italica
Also known asCalabrese · Italian broccoli · Sprouting broccoli
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 3–10 (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 |
|---|---|---|---|
| Rockwool (Mineral wool) | alkaline until pre-soaked | very high | low |
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Net pot, no medium (Bare-root) | - | - | - |
| 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 | 1 | 1 | 1 | 1 |
| vegetative | 3 | 1 | 2 | 2.2 |
Companion-growing notes
- Heavy uptake of nitrogen, calcium. Co-grown crops with the same demand will end up deficient even at "correct" EC.
- High transpiration. Regular reservoir top-ups needed during fruiting.
Aquaponics suitability
Not recommended
Fish waste alone doesn't supply enough of what this crop demands. Grows in hybrid systems with supplemental dosing, but expect active management.
Care notes
A moderate-difficulty hydroponic crop that rewards good temperature control. Dutch bucket or media bed systems with 20 cm depth for root development. EC 2.0-3.0 mS/cm. pH 6.0-7.0. Temperature: 15–22°C (critical; above 25°C, the heads become loose, yellow, and bitter; below 10°C, growth stalls). Moderate to high light (DLI 15-22 mol/m2/day). From transplant to main head harvest: 60-80 days depending on variety. Harvest the central head when buds are tight and deep green, before any yellow petals appear. Cut 10–15 cm below the head. Most varieties then produce smaller side shoots (2–5 cm heads) for 3-4 weeks of additional harvesting. Calcium and boron supplementation prevents hollow stem (a common quality defect). Caterpillars (cabbage looper, diamondback moth) are the primary pest; BT spray is effective. For hydroponic growers, broccoli occupies a lot of space for a single head; side-shoot varieties ('Belstar', 'Gypsy') maximize the harvest from each plant. The high nutrient demand and cool temperature requirement make broccoli more suited to fall/winter greenhouse production.