Cauliflower
Brassica oleracea var. botrytis
Also known asCauli · Chou-fleur
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 3–10 (winter low around -40°C)
- Frost
- tolerates light frost
- 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
One of the most challenging brassica crops for hydroponics due to strict temperature requirements and sensitivity to stress. Large containers or media beds (20 cm depth). EC 2.0-3.0 mS/cm. pH 6.0-7.0. Temperature: 15–20°C during curd formation (critical; temperatures above 25°C or below 5°C cause 'buttoning' (premature, undersized curds), riciness (loose, grainy texture), and browning). The narrow temperature window is the primary difficulty. Moderate to high light (DLI 15-22 mol/m2/day). From transplant to harvest: 65-85 days depending on variety. Harvest when the curd is 15–20 cm diameter, compact, and white (or the target color for colored varieties). If yellow or purple spots appear on white curds, light exposure is the cause; check that the blanching is effective. Calcium and boron supplementation prevents hollow stem and browning of the curd. Caterpillars and aphids are common pests. For hydroponic growers, the temperature sensitivity makes cauliflower a fall/winter crop in most setups. Mini cauliflower varieties ('Snowball Y Improved', 'Snow Crown') produce smaller heads faster and are more forgiving.