How to grow Fennel

At a glance

🌱 Grow your Fennel with GardenDex

• Reminders to water it, timed to your weather and whether it's in a pot
• Frost and disease alerts for your garden, the night before
• Follow it from seed to harvest, and see what your garden grew in $
• Point your camera at any plant or bug to identify it

🗓️ When to plant

Sow seeds directly outdoors in mid-spring after the last frost, or in late summer for autumn harvest in mild climates.

🌰 How to plant

1. Sow seeds directly into garden soil or pots; do not transplant as fennel has a sensitive taproot.
2. Scatter seeds thinly on the soil surface and press gently; they need light to germinate.
3. Keep soil moist until seedlings emerge in 7–14 days.
4. Thin seedlings to final spacing once they have 2–3 leaves.

💧 Care

• Water regularly during dry spells to prevent bolting and to encourage bulb development.
• Mulch around plants to retain moisture and suppress weeds.
• Deadhead flowers if you want to extend leaf and bulb production, or leave them to set seed.
• Stake tall varieties in windy locations to prevent flopping.

🧺 Harvest

Harvest bulbs when they reach 7–10 cm (3–4 in) diameter by cutting at soil level; pick leaves and fronds anytime for fresh use. Collect seed heads in late summer when they turn brown and papery, then dry and thresh for seeds.

🐛 Common problems

Aphids: Spray with water or insecticidal soap; encourage ladybugs by planting flowers nearby.

Root rot: Ensure soil drains well and avoid overwatering, especially in cool, damp conditions.

Fennel moth caterpillars: Remove affected leaves by hand or use neem oil if infestations are severe.

🤝 Companion plants

💚 Good neighbours: Tomatoes, Cucumber, Dill, Caraway

⚠️ Keep apart from: Beans, Kohlrabi, Most brassicas

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