Florence fennel

Florence fennel: plant 25 cm (10 in) apart in the row and 45 cm (18 in) between rows, 4 per square. No known bad neighbours.

Key facts

Spacing in the row	25 cm (10 in)
Between rows	45 cm (18 in)
In a 30 cm (1 ft) square	4 per square
Sun	Full sun, 6–8 hours a day
Root depth	25 cm (10 in)
Height when grown	70 cm (28 in)
Crop rotation group	Roots and onions
Support	None needed

Sowing and germination

How it is started	Sown straight into the bed, started in trays
Seeds per hole	3
Plants kept after thinning	1
Seeds per metre of row	12
Sowing depth	1 cm (0.4 in)
Soil temperature	from 4 °C, best 16–21 °C
Days to emerge	7–14 days
Light while germinating	Needs darkness, cover well
Before sowing	nothing needed
When to sow	Indoors 4 weeks before the last frost; outdoors before the last frost; soil at least 5 °C

From seedling to plant

After emergence	12–18 °C; take the cover off as soon as they show
Pricking out	at 2 true leaves
Takes transplanting	Easily
Hardening off	5–7 days
Life cycle	Annual
Cold tolerance	Takes a light frost
Soil	Rich, with compost, stays moist, pH 6–7
In a pot	6 L, 20 cm (7.9 in)
Watering	Water when the soil is dry two fingers down; while leaves grow
Feeding	Moderate; at planting, while growing
Support and training	None needed

Harvest and planning

Days to first harvest	80–100 days, from sowing
Ready when	The bulb is the size of an egg or bigger
Harvest window	All at once, 2–4 weeks
Sow again every	14 days
Typical yield	0.3–0.6 kg per plant
Botanical family	Apiaceae
Watch out for	Bolting in heat, slugs and snails

Plan Florence fennel in your garden

Open the free planner, drop Florence fennel onto a bed and see how many plants fit.

Start Planning Your Garden

Sowing and harvest

Sow outdoors	Jun–Jul
Harvest	Sep–Nov

My dates for this crop

My country Last spring frost where I live

Give the date once and this page, the sowing calendar and the planner all follow it.

Months for a temperate climate: about a month later in the north and a month earlier in the south. Give your own last frost date for exact dates.

What to plant next to Florence fennel →

From the same family

Plants of the Apiaceae family share diseases and pests, so they follow each other in the rotation only after a break.

Grown much the same way

Crops that need about the same room and care, from another family.

Sources

The values on this page marked as checked come from these sources: spacing, sowing depth, germination, soil, timing and safety notes, each against the source named here.

Culinary Use and Culture of Herbs (from the California Master Gardener Handbook; R10/2019) — UC Cooperative Extension, Master Gardeners of Orange County for: spacing in the row; checked 2026-10-30

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