Broccoli
Calabrese, Sprouting Broccoli, Italian Sprouting
Cool-season crop — matures best in fall (transplant late summer) or early spring. Head quality degrades rapidly in heat (turns yellow). Harvest central head before florets open; side shoots follow for weeks. Monitor closely for cabbage worms. Needs consistent nitrogen fertilization. Space 18–24" for full-size heads.
- Germination
- 5–10 days
- Soil temperature
- 7–29 °C
- Harvest after planting
- 60–80 days
- Spacing
- 45–60 cm
When to plant broccoli
Start seeds indoors 6–8 weeks before your last spring frost, and plant out 2–4 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 broccoli
- 1
Sow indoors
Sow 6 mm deep 6–8 weeks before the last frost and keep at 21–24 °C until seedlings appear, then grow on in bright, cool light so they stay stocky.
- 2
Plant out
Plant out 2–4 weeks before the last frost, 45–60 cm apart. Broccoli likes cool weather; for an autumn crop, plant out again in late summer.
- 3
Feed and protect
Feed with nitrogen at planting and again when heads start to form. Net against cabbage white caterpillars.
- 4
Harvest
Cut the main head while the buds are tight and dark green, before any yellow shows, 60–80 days after planting out. Side shoots follow for weeks.
Growing conditions
Light
Full sun
Water
Medium water
Temperature
4–24 °C
Frost tolerance
Frost-hardy — tolerates frost
Days to maturity
60–100 days
Plant spacing
45 cm
Ideal soil pH
7–7.5
How Tomatograph watches your broccoli
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.
- Within a week of maturityHarvest-window reminder based on when you planted.
Broccoli questions
- When should I plant broccoli?
- Start seeds indoors 6–8 weeks before your last spring frost, and plant out 2–4 weeks before it.
- How long do broccoli seeds take to germinate?
- Usually 5–10 days at a soil temperature of 7–29 °C.
- How long until I can harvest broccoli?
- About 60–80 days after planting out, depending on variety and weather.
- How far apart should I plant broccoli?
- Allow 45–60 cm between plants.
- What grows well with broccoli?
- Good neighbours include onion, garlic, lettuce, celery.
Growing guide written by Tomatograph. Planting figures from openplantdb (CC0 1.0). Zone frost dates are averages from openplantdb (CC0 1.0).