Invasive in some states
This plant is assessed as invasive in parts of the US. It is not illegal, but consider a non-invasive alternative and check your local guidance before planting it.
Florence Fennel
Foeniculum vulgare var. azoricum
herbFlorence Fennel (also called finocchio) is grown not for seed but for the swollen white bulb of overlapping leaf bases at the soil line, with a delicate sweet anise flavor that mellows beautifully when roasted or shaved raw into salads. The variety is more demanding than herb fennel and needs cool steady conditions to form a proper bulb.
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Sun
full sun
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Water
Every 3 days
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Harvest
~90 days
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Difficulty
medium
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Lifecycle
biennial
Leaves year 1, flowers year 2
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Spacing
8-12 in apart
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Planting Depth
1/4 in
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Soil pH
6.5-8.0
Growing Details
Soil Type
Rich, well-draining
Hardiness Zones
Zones 4 – 9
Grown as an annual — this range is its winter hardiness, but you can grow it for a single season in any zone.
When to Fertilize
Light feed at sowing; side-dress at 4 weeks
Fertilizer
Balanced 5-10-10 or fish emulsion
🌱 Growing Guide
Florence fennel prefers cool weather; sow in early spring for a summer harvest or, in most climates, in mid to late summer for a fall crop (sowing after midsummer produces the best bulbs because cooling days slow bolting). Direct-sow 1/4 in deep in full sun on well-drained loamy soil with consistent moisture. Thin to 8 to 12 in apart. Hill soil around the base as the bulb swells, similar to leeks, for whiter tender bulbs. Florence bolts quickly under heat or moisture stress, so mulch and irrigate steadily.
Planting Calendar
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Direct sow
Apr 1
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Projected first harvest
Jun 30
JJan
FFeb
MMar
AApr
MMay
JJun
JJul
AAug
SSep
OOct
NNov
DDec
✅ Plant alongside
Good neighbors that attract beneficial insects or deter pests
- Lettuce — Both prefer cool conditions and shade lettuce gently during summer fennel growth
- Spinach — Quick early companion that finishes before fennel needs the room
- Dill — Attracts parasitic wasps that hunt fennel pests
- Marigolds — Suppress nematodes and add color to the bed
❌ Keep away from
TomatoBeansMost plants
🛡️ Pest & disease prevention
Proactive ways to stop trouble before it starts — tap a name with an arrow for its full guide
Sow after midsummer for fall harvest, mulch deeply to keep roots cool, and water consistently; choose slow-bolt varieties like Perfection or Mantovano
Blast with water and encourage ladybugs; avoid heavy nitrogen which drives soft sappy growth
Set beer traps or iron phosphate bait around young plants; remove garden debris where slugs hide
Hand-pick if needed, but consider leaving some plants; black swallowtail butterflies use fennel as a host
🌾 Harvest & storage
Florence fennel is ready 60 to 90 days from sowing, when the bulb reaches tennis-ball size. Cut at the soil line with a sharp knife (leave the roots in the ground; they will sometimes resprout smaller bulbs). The fronds are also edible and useful as a delicate herb. Refrigerate bulbs in perforated bags for up to 10 days; they soften with longer storage.
🥗 Nutrition & benefits
About 31 calories per 100 g raw with 3.1 g fiber, 12 mg vitamin C, 414 mg potassium, and 49 mg calcium. The bulb supplies anethole, the same anise-flavor compound found in fennel seed and star anise, which has been studied for digestive benefits.
For educational and informational purposes only — HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.