How to grow cauliflower
Overview
Cauliflower (Brassica oleracea var. botrytis) is a cool-season brassica grown for its dense white curd (head). It demands consistently cool temperatures (15–20°C) and steady moisture to form tight heads without bolting or buttoning. Success hinges on timing planting to avoid heat stress.
Varieties
- Snowball — Classic white-skinned variety with reliable head formation; good for spring and autumn crops in cool to temperate zones.
- All Year Round — Versatile Australian-bred variety that tolerates a range of conditions; suitable for successive sowing in temperate areas.
- Graffiti — Striking purple-headed cauliflower with mild flavour; retains colour when cooked briefly; high in anthocyanins.
- Cheddar — Orange-curd cauliflower rich in beta-carotene; sweet, nutty taste; adds colour to dishes.
Soil Preparation
Cauliflower thrives in deep, fertile, loamy soil rich in organic matter. Aim for pH 6.0–7.0; add lime if pH is below 6.0 to prevent clubroot. Work in 5–10 cm of well-rotted compost or manure before planting to boost nutrients and moisture retention.
Growing Guide
Plant in full sun in fertile, well-drained soil with pH 6.0–7.0. Space seedlings 45–60 cm apart in rows 60–75 cm apart. Transplant deeply, burying the stem up to the first true leaves to encourage strong rooting. Water consistently to keep the soil evenly moist—never allow drying or waterlogging. Use shade cloth in warmer zones to delay bolting.
Sowing
Sow seed 6 mm deep in seed trays or direct in garden. Germination takes 5–10 days at 20°C. Transplant seedlings with 4–6 true leaves, spacing 45–60 cm apart. For direct sow, thin to final spacing and protect from birds with netting.
Care
Feed every 2–3 weeks during active growth with a balanced nitrogen-rich fertiliser (e.g., fish emulsion or blood and bone). Side-dress with compost or well-rotted manure when curds begin to form. Remove yellowing lower leaves to improve airflow and reduce disease risk. Mulch to keep roots cool and soil moisture even.
Companion Planting
Good companions include beans, celery, dill, onions, potatoes, and spinach. Do not plant near other brassicas (broccoli, cabbage, kale) to reduce shared pest and disease pressure. Avoid strawberries, which are said to inhibit cauliflower growth.
Common Pests & Risks
Cabbage white butterfly caterpillars are the primary pest—use fine insect netting or Bacillus thuringiensis (Bt). Aphids cluster on new growth; blast off with water or apply neem oil. Slugs and snails can damage young plants; control with iron-based pellets or beer traps. Keep area weed-free to reduce hiding spots.
Harvesting
Harvest when heads are compact, firm, and white (or coloured for varieties). Cut the stem below the head with a sharp knife, leaving a few outer leaves for protection. Heads left too long will loosen and become bitter; harvest promptly before the curd separates.
In the Kitchen
Harvested heads keep fresh in the fridge for up to 2 weeks if stored in a plastic bag. Cauliflower is versatile: roast whole or florets, steam, blanch for freezing, or eat raw in salads. Avoid overcooking to prevent mushiness and strong sulphurous odour.
Troubleshooting
Loose, leafy heads: caused by too-high temperatures or inconsistent watering. Yellow heads: sun exposure—tie outer leaves over the curd to blanch. Bolting (premature flower stalk): sudden heat or transplant shock. Buttoning (tiny heads): nutrient deficiency or stress from cold or drought. Purple tinge on white varieties: exposure to sun; harmless but avoid by blanching.