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 moderately demanding hydroponic crop that rewards good temperature control. Use Dutch bucket or media beds with about 20 cm of depth for the roots. Hold EC around 1.8-2.5 mS/cm and pH 6.0-7.0. Temperature is critical, best at 15–22°C: above 25°C the heads go loose, yellow and bitter, and below 10°C growth stalls. Give moderate to high light, 17-22 mol/m2/day. From transplant to the main head is about 60 to 80 days. Cut the central head while the buds are tight and deep green, before any yellow petals show, taking 10–15 cm of stalk; most varieties then give smaller side shoots for three to four weeks. Steady calcium and boron prevent hollow stem. Caterpillars (cabbage looper, diamondback moth) are the main pest, controlled with a Bacillus thuringiensis spray. A single head takes a lot of space, so side-shooting varieties such as Belstar or Gypsy make better use of each plant. The high feeding demand and cool requirement suit fall and winter greenhouse production.