Information About Fennel Bulb

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Greenhouse Fennel Care – How To Grow Fennel In A Greenhouse

By Amy Grant

Fennel is a delicious plant that is commonly used in Mediterranean cuisines. It can be grown in USDA zones 5-10 as a perennial. However, if you are in a cooler zone, have you ever wondered about growing fennel in a greenhouse? You can find out in this article.

Can I Regrow Fennel – Tips On Growing Fennel In Water

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No Bulbs On Fennel: Getting Fennel To Produce Bulbs

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So you're fennel is not producing bulbs. Sure, the rest of the plant looks good but when you decide to dig one up, there's no bulb on the fennel. Why is the fennel not producing bulbs? Click this article to find out how to get fennel to form bulbs.

Growing Florence Fennel In The Vegetable Garden

By Bonnie L. Grant, Certified Urban Agriculturist

Florence fennel is the bulb type of fennel that is eaten as a vegetable. All parts of the plant are fragrant and can be used in culinary applications. Florence fennel cultivation tips can be found in this article.

Fennel (Foeniculum vulgare)

There are two types of fennel, herb and Florence, both of which are extremely popular – as well as highly ornamental – and much loved by cooks for use in the kitchen for their aniseed-liquorice flavours.

The perennial herb, leaf fennel or sweet fennel is grown for its aromatic, aniseed-flavoured feathery leaves and its seeds, both of which are used to flavour dishes. The foliage is also very attractive and ornamental, and looks great in beds and borders. Florence fennel (Foeniculum vulgare var. dulce) is grown as a tender annual vegetable, loved for its crunchy, swollen stems. The leaves can also be used as a herb.

How to grow fennel


Herb fennel will grow perfectly well in a position in full sun or in partial shade. Florence fennel needs a position in full sun. Both grow best in a fertile, moist but well-drained soil. Dig in plenty of organic matter – such as garden compost, well-rotted manure or other soil improver – especially in very well-drained sandy soils to hold moisture.

Fennel varieties

Herb fennel

There are only two varieties. The straight species, Foeniculum vulgare, with green leaves and bronze fennel, Foeniculum vulgare Purpureum, with purple-bronze coloured leaves.

Florence fennel

There are a few excellent varieties, including Amigo, di Firenze, Sirio and Victorio.

Sowing fennel

Herb fennel

Sow seeds directly outdoors from March to May in well-prepared soil where you want them to grow. When seedlings are large enough to handle, thin them out to 30-45cm (12-18in) apart.

Alternatively, sow indoors in spring in pots or modules filled with good seed sowing compost and transplant out 45-50cm (18-20in) apart after hardening off.

Florence fennel

Direct sow seeds thinly outdoors from March/April to July into well-prepared soil when temperatures reach around 13-18°C (55-64°F). Sowing in cold soil or during cold weather can induce bolting (running to seed prematurely) before the crop is ready to harvest. When seedlings are large enough to handle, thin them out to 30cm (12in) apart.Water well until plants are established.

Make regular sowings for successional cropping.

Planting fennel

You can buy young plants of herb fennel – both green-leaved and bronze – from garden centres, which are best planted outside in spring or early summer.

Dig over the planting area, incorporating some organic matter – such as compost or leafmould, especially if the soil is heavy clay. Dig a good sized hole big enough to easily accommodate the rootball.

Place the rootball in the planting hole and adjust the planting depth so that the crown of leaves is at soil level.

Mix in more organic matter with the excavated soil and fill in the planting hole. Apply a general granular plant food over the soil around the plants and water in well.

Florence fennel doesn't always transplant well and it is best grown from seed, sown direct where you want it to crop.

How to care for fennel

Herb fennel

It may be necessary to keep the soil moist by watering regularly during prolonged dry periods in summer.

Removing developing flower heads will prolong the supply of leaves, but the seeds themselves are also useful and can be used in cooking.

Fennel is a hardy perennial herb, which will die back to ground level in winter. When this happens, tidy up the plants by cutting back flower stems and removing dead and dying foliage.

Florence fennel

Florence fennel can bolt (run to seed prematurely) if there is a check in growth. Keep the soil moist by watering regularly particularly during hot, dry periods in summer.

Feed every two to three weeks in summer with a high potash plant food.

Keep the soil around plants weed free and earth up around the bulbs during the growing period to make them sweet and white.


Herb fennel

Fennel leaves can be harvested at any time they are available.

For fennel seeds, allow the flowers to fade and harvest once the seed heads have fully ripened and the seeds have turned brown. Seeds can be used fresh or dried for winter use.

Florence fennel

Harvest at ground level once the stems are sufficiently swollen in size and are roughly tennis ball size.

If you leave the roots in the ground they may re-shoot and the small shoots can be used in salads.

Tips & Information about Fennel Bulb - garden

Foeniculum vulgare
Foeniculum vulgare var. dulce

taken from The Georgia Fruit and Vegetable Book by Walter Reeves and Felder Rushing

Fennel is a European herb known for its aromatic seeds and tender, fragrant leaves. This herb has a wonderful anise-like or licorice-like flavor. Florence Fennel, commonly called Finocchio, develops a bulb-like base used fresh or steamed. Common Fennel develops a plant that can be 4 feet tall when it is in flower. Finocchio develops a bulb-like rosette of foliage, which is harvested before it bolts. Both are tender perennials grown as annuals.

You may start Fennel or Finocchio indoors under lights about 6 weeks before the frost-free date (average date of last frost) for a summer crop and start them under lights in late summer for a fall crop. You can also sow seed directly in the garden after the last heavy freeze. Seed can withstand a frost but if plants are already up, they may be nipped. Started plants are not likely to be available in garden centers they do not transplant well because they have tap roots. The number of plants depends on your tastes you may want 6 or more if you like Fennel or Finocchio (or swallowtail butterflies!).

Plant Fennel and Finocchio in a sunny location with well-prepared soil. Since they get quite large and reseed vigorously, locate them where they will have room and will not shade out lower-growing plants.

Prepare the soil. Sow seed directly in the garden. Thin seedlings to about 8 inches apart when they are 4 inches tall and use them in soups or sauces. Fennel and Finocchio do not tolerate transplanting well. Start them in peat pots, which you can plant without disturbing the roots. Sow several seeds per pot and thin to 1 apiece when they have germinated. Set the plants 8 inches apart in well-prepared soil.

After it has started to grow, Fennel or Finocchio require little care. Water them during dry weather, providing 1 inch per week.

Harvest the tender leaves when the plants are 6 to 10 inches tall. Keeping the plants cut back will extend the harvest but eventually the plants will bolt and make flower stalks. To harvest seeds, cut the heads when the seeds are mature but before they begin to shatter. Hang the heads upside down in brown paper bags to finish drying, catching the seeds as they fall. Tie harvested leaves into small bundles and hang them in a warm, dry place, or dry leaves on a window screen. Store dried leaves and seeds in airtight containers for later use. Cover Finocchio bulbs with soil to blanch them when they are 2 or 3 inches in diameter. Harvest the bulbs before they bolt in hot weather. In the cool weather of fall, production may be extended until freeze-up. Late in the season, allow a few flower heads to mature and the seed to drop, which will produce seedling plants for the next year. Since they do not transplant easily, harvest the tender leaves and then hoe out the plants if they are in the way of other things. Fennel, along with Dill and Parsley, is a favorite food of black swallowtail butterfly larvae. These large black-and-yellow-striped caterpillars do not eat much but make spectacular butterflies. Collect the chrysalises that form and hatch them for a fun summertime kids’ project.

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