How to grow florence fennel
Overview
Florence fennel (Foeniculum vulgare var. azoricum) is a vegetable grown for its swollen, crisp bulb with a mild anise flavour. It thrives in cool to warm conditions and requires consistent moisture and full sun to produce a quality bulb.
Varieties
- Florence Fennel — Standard variety with large, tender bulbs and mild anise flavour.
- Zefa Fino — Quick-maturing variety ideal for cooler climates, producing uniform bulbs.
Soil Preparation
Florence fennel prefers rich, well-drained soil with a pH of 6.0–7.0. Add well-rotted compost before planting. Avoid heavy clay or waterlogged soil to prevent root rot.
Growing Guide
Sow seed directly 10mm deep in well-drained, fertile soil, spacing 30cm apart in rows 45cm apart. Thin to 20cm for best bulb size. Keep soil evenly moist and avoid transplanting if possible, as fennel dislikes root disturbance. Mulch to retain moisture and suppress weeds.
Sowing
Sow seed 10mm deep, 30cm apart, directly in the garden after frost. Germination takes 10–14 days at 15–20°C. Transplanting is not recommended due to root disturbance.
Care
Feed with a balanced liquid fertiliser every 2–3 weeks during active growth. Remove any flower stalks promptly to direct energy into the bulb. Keep soil consistently moist but not waterlogged.
Companion Planting
Florence fennel can inhibit the growth of nearby plants, especially beans, tomatoes, and coriander. Avoid planting it near these. Good companions include dill, but keep them separate to avoid cross-pollination.
Common Pests & Risks
Aphids and caterpillars (especially cutworms) may attack fennel. Use insecticidal soap for aphids and hand-pick caterpillars. Slugs can be a problem in wet conditions; use barriers or organic pellets.
Harvesting
Harvest bulbs when they are 8–10cm wide, plump, and firm, usually 12–16 weeks after sowing. Cut the stem just above the soil line; the bulb can be stored in the fridge for up to a week.
In the Kitchen
Use bulbs raw in salads, roasted, or braised. Leaves and seeds are also edible. Store bulbs in the fridge for up to a week.
Troubleshooting
Bolting (premature flowering): caused by heat or drought stress. Keep soil moist and plant in cool season. Small bulbs: due to poor soil or overcrowding. Thin to 20cm spacing. Leaf yellowing: overwatering or nitrogen deficiency. Adjust watering and feed.