Cauliflower
White Cauliflower, Purple Cauliflower, Romanesco, Cauliflower, Broccoflower, Broccoli, Cape-Broccoli
Most demanding brassica — needs consistent water, fertility, and cool temperatures. Blanch white varieties by tying outer leaves over the head when it reaches 2–3" (prevents yellowing). Very sensitive to heat; fall planting often more successful. Needs boron micronutrient; amend soil if hollow stems appear.
- Germination
- 5–10 days
- Soil temperature
- 7–29 °C
- Harvest after planting
- 55–80 days
- Spacing
- 45–60 cm
When to plant cauliflower
Start seeds indoors 6–8 weeks before your last spring frost, and plant out 3–4 weeks before it.
Dashed line: typical last spring frost in zone 7 (Apr 5). Zone dates are averages; most of the UK is zone 8–9, central Europe 6–7 and the Baltics and Scandinavia 4–6. In the app, Tomatograph uses your garden's own frost dates.
How to grow cauliflower
- 1
Sow indoors
Sow 6 mm deep 6–8 weeks before the last frost and grow seedlings cool and bright.
- 2
Plant out
Plant out about four weeks before the last frost, 45–60 cm apart, into rich, firm soil. Cauliflower is the fussiest brassica: any check in growth gives small, early heads, so autumn crops are often more reliable.
- 3
Keep it steady
Water consistently and feed well. Hollow stems point to boron deficiency in the soil.
- 4
Blanch and harvest
When the curd is 5–8 cm across, fold the outer leaves over it to keep white varieties white. Cut while firm and tight, 55–80 days after planting out.
Growing conditions
Light
Full sun
Water
High water
Temperature
4–22 °C
Frost tolerance
Frost-hardy — tolerates frost
Days to maturity
80 days
Plant spacing
45 cm
How Tomatograph watches your cauliflower
Tomatograph checks your local forecast every morning and only speaks up when one of these applies to your garden.
- First frost within 14 daysReminder to mulch the roots before winter.
- 3 days at 35 °C or aboveHeat-wave alert while plants are flowering or fruiting: shade and water early.
- Humidity above 80% for 48 hoursCheck for black rot, which thrives in those conditions.
- Under 5 mm of rain forecast over 3 daysWatering reminder: water deeply at the base, early in the morning.
- Within a week of maturityHarvest-window reminder based on when you planted.
Cauliflower questions
- When should I plant cauliflower?
- Start seeds indoors 6–8 weeks before your last spring frost, and plant out 3–4 weeks before it.
- How long do cauliflower seeds take to germinate?
- Usually 5–10 days at a soil temperature of 7–29 °C.
- How long until I can harvest cauliflower?
- About 55–80 days after planting out, depending on variety and weather.
- How far apart should I plant cauliflower?
- Allow 45–60 cm between plants.
- What grows well with cauliflower?
- Good neighbours include onion, garlic, lettuce.
Growing guide written by Tomatograph. Planting figures from openplantdb (CC0 1.0). Zone frost dates are averages from openplantdb (CC0 1.0).