Florence Fennel
Finocchio, Bulb Fennel, Sweet Anise
Grown for its swollen, anise-flavored bulb. Direct sow in early spring (bolts in heat) or late summer for fall harvest. Keep away from tomatoes, peppers, and most other vegetables — allelopathic. Blanch the bulb by hilling soil around it as it swells for milder flavor. Harvest when bulb reaches tennis-ball size. Fall crops have better quality than spring.
- Germination
- 7–14 days
- Soil temperature
- 16–24 °C
- Harvest after sowing
- 75–90 days
- Spacing
- 15–30 cm
When to plant Florence fennel
Sow outdoors 12–14 weeks before your first autumn frost.
Dashed line: typical first autumn frost in zone 7 (Nov 1). 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 Florence fennel
- 1
Sow for autumn
Florence fennel bolts in heat and long days, so the best crop comes from a summer sowing 12–14 weeks before the first autumn frost. Sow direct; it resents being moved.
- 2
Keep it apart
Grow it away from tomatoes, peppers and beans, which it can hold back.
- 3
Water and earth up
Water steadily; dry spells trigger bolting. Draw soil around the swelling bulb for a milder, paler result.
- 4
Harvest
Cut the bulb at soil level when it reaches tennis-ball size, 75–90 days after sowing.
Growing conditions
Light
Full sun
Water
Medium water
Temperature
4–27 °C
Frost tolerance
Frost-hardy — tolerates frost
Days to maturity
65–90 days
How Tomatograph watches your Florence fennel
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 root rot, which thrives in those conditions.
- Within a week of maturityHarvest-window reminder based on when you planted.
Florence Fennel questions
- When should I plant Florence fennel?
- Sow outdoors 12–14 weeks before your first autumn frost.
- How long do Florence fennel seeds take to germinate?
- Usually 7–14 days at a soil temperature of 16–24 °C.
- How long until I can harvest Florence fennel?
- About 75–90 days after sowing, depending on variety and weather.
- How far apart should I plant Florence fennel?
- Allow 15–30 cm between plants.
- What grows well with Florence fennel?
- Good neighbours include dill.
Growing guide written by Tomatograph. Planting figures from openplantdb (CC0 1.0). Zone frost dates are averages from openplantdb (CC0 1.0).