How to Grow Fennel
Know Your Fennel – Flavour & Kitchen Uses:
- Bulbing / Florence fennel – sweet anise crunch; shave raw into salads, roast wedges, braise with fish or grill for caramel notes.
- Leaf or wild fennel – feathery fronds and aromatic stems; use like dill in herb butters, sauces and as a fish garnish. Seeds flavour breads, biscotti and sausages.
Seeds per Gram: ≈ 200 – 250 seeds per gram
Optimal Germination: 10 – 30 °C (germinates in 7 – 14 days)
Feed Requirements:
- Moderate feeder. Mix 5 cm of compost into the bed before sowing, then:
- When bulbs begin swelling: side-dress row with nitrogen-rich fertiliser.
- Repeat light liquid feeds every fortnight if foliage pales.
Growing Notes:
Climate & Timing:
- A cool-season vegie that bolts in hot, long-day weather. Sow direct early spring or late summer for autumn/winter harvest.
- In mild climates a mid-winter sowing gives spring bulbs; in cold zones start seed indoors 4–6 weeks before last frost and transplant cautiously.
Sowing & Spacing:
- Direct sow 5-8 mm deep, 30-40 cm apart in rows 40 cm apart. Ensure to thin bulbing varieties 30 cm once plants reach 10 cm tall to ensure good sized bulbs.
- For succession, sow 1 m of row every 3 – 4 weeks.
Soil & Water
- Prefers fertile, well-drained loam, pH 6.5 – 8.0;
- Keep soil evenly moist;
- Drip irrigation prevents split stems and bolting stress.
Cultural Tips
- Mulch to keep soil cool and suppress weeds.
- As bulbs swell, hill 5 cm of soil around bases to keep them white and tender.
- Avoid disturbing roots; fennel dislikes transplant shock.
- If starting as seedlings ensure deep pots or cells so less root disturbance when planting out. Ensure that you transplant before roots start 'curling' or get too crowded.
- Companion planting: fennel can inhibit some neighbours—grow at bed ends or amongst flowers rather than beside beans or coriander.
Common Problems:
- Bolting: triggered by heat, drought or damage—keep soil moist, sow bolt-resistant cultivars such as ‘Orion’.
- Aphids, thrips, cabbage moth larvae: blast off with water, use insecticidal soap or encourage lacewings.
- Cutworms & slugs: use collars on seedlings; hand-pick pests at dusk.
- Bulbs not forming: often too-hot weather, irregular watering or sowing common (non-bulbing) fennel—timing and variety choice are key.
Harvesting:
- Leaves: snip fronds anytime once plants are 15 cm tall; use fresh or freeze in herb butter.
- Bulbs: cut at root crown when bases reach 6 – 10 cm across and feel firm.
-
Seeds: clip umbels when they brown; dry in paper bags, then winnow.
Storage & Use:
- Bulbs keep 5 – 7 days in a perforated bag in the fridge.
- Blanch-and-freeze slices for soups.
- Dried seed stores 12 months in airtight jars.
With steady moisture, rich soil and clever timing, fennel rewards you with feathery herbs, succulent bulbs and fragrant seeds—three harvests from one elegant plant.
