How to grow Florence fennel

BBC Gardeners' World Magazine

Published: Wednesday, 13 March 2019 at 1:45 pm

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We show you how to grow Florence fennel, in this start-to-finish Grow Guide.

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Spacing:

30 apart

Florence fennel is the bulbous edible version of the more familiar herb, sharing the same distinctive aniseed flavour.

The bulb is in fact the swollen base of the stem. It can be a little tricky to grow, but with the right care and attention, a homegrown crop is well worth the effort. Freshly picked fennel makes a great addition to summer salads but is also delicious cooked as an accompaniment to meat dishes, or on its own.

Follow the expert advice in this guide to grow your own Florence fennel.

Sowing Florence fennel

Growing fennel from seed

If you want to get an early start with Florence fennel, sow seeds into modules under cover. Sow one seed per module, as the seedlings don't like having their roots disturbed when transplanted. Water in well and keep moist.

When the roots fill the modules, ‘harden off’ the seedlings and plant out into a well-prepared and fertilised beds, when there's no danger of frost.

Later in the season, you can sow directly into well-prepared, warm soil. Place seeds in rows, approximately 1.5mm deep, thinning to 30cm apart.

Looking after fennel plants

Florence fennel thrives in warm, sunny and moist conditions. The key to success is to prepare a bed of well-drained, fertile soil in an open site. Once your seedlings have been planted out, make sure they're regularly watered.

Your plants won't be happy if left to dry out, or if an unexpected frost takes them by surprise. Any shock to the system will affect the growth of the tender, edible bulb and cause the plant to bolt, flower and set seed quite rapidly. You can earth up the bulbs as they start to swell, but this isn't always necessary.

Give plants a boost every couple of weeks with a high potash feed.

Harvesting Florence fennel

Harvesting fennel bulbs

Your Florence fennel bulbs will be ready to harvest in about 14 weeks. Cut the bulb above the soil, but leave the root in the ground. This may re-sprout and produce a second harvest of smaller, tender shoots.

Florence fennel seeds

Storing Florence fennel

Bulbs are best used soon after cutting. They're tasty both raw in salads and cooked. The leaves and stem can also be used as seasoning for fish and in salads. Even the seeds can be used if your plants have bolted.

Looking for inspiration on how to use your crop? Our friends at olive have curated a delicious collection of fennel recipes, including their indulgent Italian fennel bake.

Problem solving: fennel

Choose bolt-resistant varieties, as Florence fennel is very prone to bolting, particularly when sown early in the season.

Protect young plants from slugs and snails.

Organic tip

To keep plants moist, use a thick mulch over the soil which will also help to suppress weeds.

Florence fennel growing

Florence fennel varieties to grow

‘Sirio’ – quick to mature, this variety is best sown in May-June for harvesting in autumn
‘Perfection’ – this bolt-resistant variety produces medium-sized bulbs with a delicate aniseed flavour. It's a good variety for early sowing
‘Cantino’ – a bolt-resistant variety with good strong flavour
‘Amigo’ RHS AGM – good, regular, but slightly flatter bulbs and is bolt-resistant
‘Colossal’ – a bolt resistant variety that produces a very large bulb

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