Quick Guide to Growing Fennel

  • Plant fennel in spring after the last frost. It’s a great option for growing in raised garden beds, containers, and in-ground gardens.
  • Space fennel plants 4 to 12 inches apart, depending on the variety. Grow them in an area that gets at least 6 hours of sun and has fertile, well-drained soil.
  • For best results, improve your native soil by mixing in several inches of aged compost or other rich organic matter.
  • Promote excellent leaf production by regularly feeding with a water-soluble plant food.
  • Keep soil consistently moist and water when the top inch of soil becomes dry.
  • Harvest fennel leaves anytime, but avoid trimming more than one-third of the plant at once.

Soil, Planting, and Care

Fennel prefers soil that is fertile and drains well. Before planting, enrich your existing soil by mixing in compost or Miracle-Gro® Performance Organics™ All Purpose In-Ground Soil. If growing in pots, fill them with Miracle-Gro® Performance Organics™ All Purpose Container Mix. Both Miracle-Gro products are enriched with aged compost and provide just the right organic nutrition to get plants off to a strong start. Fennel is a sun-loving plant, so plant it where it will receive at least 6 hours of direct sun.

Plant fennel after the last spring frost. This plant can tolerate light frosts, but needs protection when young. Use a frost cloth to cover. When planting, space fennel seedlings from 4 to 12 inches apart, depending on variety. (Check the plant tag for more information.)

Be sure to keep soil consistently moist. Water regularly, giving plants at least an inch of water per week (more in hot weather). Stick your finger into the soil to check moisture; if the top inch is dry, it’s time to water.

For best results and super-strong growth, you’ll want to build on the nutritional foundation provided by starting with great soil. Regularly throughout the growing season, give your fennel and other plants (as well as the beneficial microbes in the soil) a boost of nutrition with a water soluble plant food like Miracle-Gro® Performance Organics™ All Purpose Plant Nutrition. Continue to feed every 1 to 2 weeks, following label directions.

Once blooms begin to appear, you can either pinch them to prevent the plant from going to seed, or just go ahead and let it flower, to attract beneficial insects

By Pam Dawling
Many people grow fennel as the herb, for leaves and seeds, for salads, soups, fish dishes and teas. The seeds are also used in desserts, breads, other baked goods and drinks. Or they are chewed after a meal to help the digestion. A newer crop in the U.S. is bulb fennel, with a vaguely licorice-like flavor. The crunchy white “bulb” consists of the swollen stem bases of the leaves. Fennel is also used in the seedling stage as a microgreen or baby salad mix ingredient. And even newer and more “exotic” is fennel pollen. Although this crop is used in so many forms, the basic details are the same for all types, so I’ll start with those.
Crop requirements
Fennel benefits from a rich, well-drained soil, with a pH of 5.5-6.8. Plant in a sunny spot for best results. Bear in mind that fennel is a Mediterranean crop, a cool-weather short-lived perennial normally grown as an annual. Fennel survives light frosts, but will only survive over winter outdoors (assuming you didn’t harvest the bulb) in zones 6-10. In zones 2-5 it grows as a biennial. It tolerates some heat and cold, but does best when it reaches maturity in cool weather. Depending on your climate, seed may be sown in early spring, mid-spring, late summer and early fall. Fennel grown for bulbs will not provide seed too – to get succulent bulbs, grow the plant fast, harvest before flower stems form and provide plenty of water. If water is in short supply, put bulb fennel at the top of your watering list.
There are about 200 seeds per gram, 7,000 seeds per ounce. The average direct seeding rate is 1000 seeds/100′, 700’/ounce, or an average of 4,000 transplants/ounce of seed. Each diner could eat up to five fennel bulbs over a season.
Fennel is not troubled by many insect pests or diseases. You might find aphids or whiteflies on the leaves, but they are rarely a serious problem. Slugs can be trouble. The worst disease is root rot, which can happen if your plants get waterlogged for too long. I’ve been emphasizing the importance of enough irrigation, but don’t over-water!
Be aware that fennel itself could be a problem. In California fennel and anise are invasive plants, causing trouble in natural areas. Before planting in that state, read the California Invasive Plant Council page on fennel:
To germinate fennel successfully, the seeds must be in the dark, with a soil temperature of 60-90°F. (70°F is ideal.) Direct seed at 10 seeds/ft, in rows 18″ apart. Thin the seedlings to 6-12″ apart. Or station sow the seed, dropping three seeds together at 12” intervals along the row, later thinning to leave the strongest seedling at each station. If the soil is dry when you are sowing, soak the furrow first. Cover the seeds with 1/8-1/2” of soil. They will take about 7-10 days to emerge. To improve germination, try soaking and pre-sprouting the seed for several days.
Bulb fennel can be sown outdoors as early as 2-5 weeks before the average last frost date in spring, but when the danger of hard frost (28°F) is over. Beware – early spring sowings are more likely to bolt. Bulb fennel is sensitive not only to day-length, but it may also bolt if there is a sudden chill (a temperature reversal). Here in zone 7, we sow Zefa Fino March 10, for April 10-26 transplanting, along an edge of a bed with parsnips, celery and (later) asparagus beans. The transplanting date is around our last frost date. If your climate and timing give you the choice, direct sow and thin, rather than transplanting, to reduce the likelihood of bolting.
The best time to sow bulb fennel is for an autumn crop. Sow in mid- to late-summer, calculating the sowing date by working back from your hoped-for harvest date. Your last sowing date will be 90-110 days before your first fall frost. In northern latitudes, gardeners wait till the summer solstice to sow any bulb fennel. If you sow around the middle of June, you should be harvesting bulbs in mid-October. The bulbs can survive a frost or two, so there is no rush to harvest when cold weather arrives. We aim to direct sow on July 8, and July 28, in part of a carrot bed. This way we keep the fennel with its umbelliferae cousins, and make our crop rotation easier.
Transplanting is useful in areas with short springs, or short seasons overall. Fennel is said to dislike root disturbance, so if transplanting, use plugs or modules. Sow 3 seeds/cell, 1/4″ deep, in 1.5-2″ deep cells. Thin to 1 plant/cell. Transplant outdoors in mid-spring to late summer when plants are 3-4” tall, and 4-6 weeks old, before they become root-bound, and when they can be removed easily without disturbing the roots. Final spacing should be 6-12” apart, either in single rows, or in rows 18” apart. Do not crowd bulb fennel plants, especially in spring, or you will encourage bolting. The plants will grow 36” tall or more, and the stems and delicate foliage can be eaten or made into teas. Herb fennel may grow to 60”.
Varieties of bulb fennel
For fennel bulbs, also known as finocchio, or Florence Fennel, sowings after mid-summer have a better chance than spring ones of producing fat tender juicy bulbs, partly due to wetter weather as the bulbs mature, and partly as they do not having lengthening daylight to induce bolting.
For earliness, try Montebianco (mid-size round white bulb, solid stalks), Mantovano, (75-85 days, round very white large bulbs), or Parma Sel Prado, (round white smallish bulbs). All from Seeds from Italy,
Some varieties do much better in the fall: try Mantovano, Bianco Perfezione Sel Fano (80-85 days, good size, half-hollow stem) from Seeds from Italy, or Victorio (75 days) from Territorial Seeds,
For spring as well as fall, try Romanesco, (85 days, a large classic variety with thick tightly wrapped stems), generic Florence Fennel (90 days), Zefa Fino (80 days) or Trieste (90 days), a bolt-resistant hybrid from Renee’s Garden
Zefa Fino is more tolerant of stress than some of the traditional Italian varieties, so if your climate or timing is borderline, try this one.
Orion (80 days) an F1 hybrid from Johnny’s, has a higher yield potential than open pollinated fennels. (All the others I have mentioned, except Trieste, are OPs)
For cooler climates, try Victorio.
The two seasons for planting bulb fennel in zone 7 are March-April and July-August – the same dates that work for broccoli, beets and other cool weather crops. Bulb fennel is a seasonal treat that can be harvested for several weeks, but it is not a year-round vegetable in most climates. It is hardy to 15°F. If bulb fennel is new crop for you, experiment with several varieties and with sowing dates that match your other cool weather crops. The fall crop is likely to be more successful than a spring one. If your spring crop bolts before forming a good bulb, the feedback is that your weather is too hot for spring planting, so stick to fall crops in future, unless you can safely start earlier in the spring.
Rich, well-drained soil, regularly irrigated, and cool temperatures produce top quality bulbs. Plants grow best and the flavors are superior when daytime air temperatures are 60-70°F. Start to blanch the lower stems when the bulb is the size of an egg by hilling up soil around the bulb. Mulching (with organic materials such as straw or hay) can be a good strategy to trap soil moisture and cooler temperatures in spring – the bulbs will be sweeter and more tender. Clip off any seed stalks that start to grow. The bulbs will be ready about three weeks after reaching egg size.
Harvest and postharvest
The bulbs are harvested when they get to small tennis ball size. If you leave them to grow larger, the plants will probably bolt and the flavor of the bulbs will quickly become bitter. Use a sharp knife or pruners to cut the bulb free just above taproot, right at the soil line. Trim the leaf stems about 1-2″ above the bulb to prepare it for sale or storage. Bulb fennel requires 80-115 frost-free days to reach harvest.
Bulb fennel will keep in the refrigerator up to 1 week or in a cold moist place for 2 to 3 months. Best storage conditions are 32°F with 95% relative humidity. Stalks can be dried or frozen; leaves can be frozen or dried as herbs. Dried leaves should be stored in an airtight container.
Nutrition and cooking
Bulb fennel is high in vitamin C, and is also a good source of calcium, fiber and potassium. According to Southern Exposure Seed Exchange, medicinally, fennel stimulates digestion while reducing the likelihood of flatulence. It is anti-spasmodic and anti-inflammatory. It can be used to soothe bronchial coughs in the same way that dill can. It has estrogenic properties to stimulate milk flow in nursing mothers.
Because it is an uncommon crop in this country, it is probably wise to offer your customers some guidelines on how to prepare and eat it. Fennel bulbs can be eaten raw, sliced thin, in salads or with dips. They are good grilled, sautéed, or steamed whole or sliced. They are delicious boiled and served with cheese sauce or butter. Try roasting with olive oil.
Herb fennel
Fennel plants are attractive to butterflies, ladybugs, lacewings and pollinators. They can grow to 5’ tall, so plan accordingly. Herb fennels will not produce bulbs. Seeds may be direct sown or transplanted, as for bulb fennel. The color of the small seedlings of bronze fennel renders them almost invisible, so take care when weeding. Bronze fennel has thin stems and beautiful bronze feathery foliage, good for flower arrangements as well as salads and plate décor. It takes about 65 days from sowing to harvestable size. The green leaf type is even easier and up to ten days quicker to grow. Johnny’s sells a green and bronze mix. Fennel can be overwintered in mild areas (Zones 7-10) to provide seed the second summer.
The feathery foliage has a sweet anise flavor and is a tasty addition to salads, cole slaw, and dressings. To dry the leaves, bunch them and hang in a dry well-ventilated area – good air circulation is essential for success. Check the leaves for dryness once a week, for two to four weeks, until they are brittle, then crumble and store in a cool dark place.
Fennel seed
Fennel seeds are used in teas and tinctures as a digestive aid, expectorant, and a tonic for the spleen, kidneys, and reproductive system. For seeds, try Finocchio Selvatico — Wild Fennel (75 days) from Seeds from Italy, The seeds are superior to those of cultivated varieties, and the flowers are beautiful too. Johnny’s warns that too much moisture at bloom time can prevent the formation of a good crop of seeds. The seeds shed very easily, and you may not want a zillion fennel plants next year, so consider tying paper or cloth bags over the heads, before they shed.
To dry fennel seeds, wait for the flowers to turn brown. Spread the freshly gathered seeds (plump and grey-green) in a single layer on a horizontal window screen. Keep mice away. The seeds should be fully dry (and brown-green in color) in about two weeks. Store in a cool dry place.
Fennel does not cross with anything except other fennel. It is widely said (even by some seed companies!) that dill and fennel cross, and some even describe the terrible flavor of the resulting crosses.
Microgreens and flowers
The feathery seedlings make an attractive ingredient for microgreen mixes and plate garnishes. Johnny’s sells a special variety Grosfruchtiger, although any kind can be used.
Fennel pollen
Fennel pollen has recently been rediscovered as a flavor enhancer. Only a sprinkling is needed. It sells for $15/ounce, and is sometimes sold combined with salt. If you have the market, or can create it, why not try growing and collecting your own? The Atlantic magazine has an article by Hank Shaw: “Want to Try Fennel Pollen? Pick Your Own”. The article includes links to more information, including recipes. It can be added to sauces, pasta dough, and many other dishes. Good information is also available on You-Tube: How to Harvest Fennel Pollen and on the eHow site: How to Harvest Wild Fennel Pollen This article is mostly written for Californians with too much invasive feral fennel, but is useful everywhere.
Cut the fennel flower stems at 6-8”, bundle and tie 15-20 together. Cover the heads with paper bags leaving about 1” of stem sticking out of the bags. Tie the bags closed and hang them in a cool, dark and dry area with the stems pointing up. Use fans if needed. Tap the sides of the bags every couple of days for two weeks as the flowers dry. When the flowers seem dry, shake the bag vigorously. Carefully open the bags and untie the bundles. Tap each individual flower head on the side of the bag as you remove it. Tip the fennel pollen and other plant matter from the bag into a fine mesh strainer resting over a bowl or bucket. Sift the pollen through the sieve, to remove the other plant matter and the larger tiny wildlife. If you need to kill any teeny tiny wildlife, you can microwave the pollen for 10 seconds.
Each flower head will produce about 1/4 tsp. of pollen. Collecting one ounce can take an hour, so a selling price of $15 suddenly doesn’t seem outrageous. Store the pollen in an air-tight container in a cool dark place. For maximum flavor, use within a year of collection.
Pam Dawling is the garden manager at Twin Oaks Community in central Virginia. Her book, Sustainable Market Farming: Intensive Vegetable Production on a Few Acres, is available via Paypal at, or by mail order from Sustainable Market Farming, 138 Twin Oaks Road, Louisa, Virginia 23093. Enclose a check (made payable to Twin Oaks) for $40.45 including shipping. Pam’s blog is also on

Tender fennel flowers are small bright yellow florets that grow in clusters to form a delicate bouquet. With a taste similar to licorice, fennel flowers are used as flavoring in cooking and for medicinal purposes. There are two types of fennel. One is an herb, and the other is a vegetable.

Herb Fennel vs. Vegetable Fennel

Most people think of fennel as a vegetable, not realizing there is also an herb fennel. Each has similar properties and all parts of each are edible. Both are known for their licorice or anise flavor.

Herb Fennel

According to the University of Illinois Extension, herb fennel (Foeniculum vulgare) is cultivated for seeds.

  • You can plant extra if you wish to harvest flowers and seeds.
  • The fennel herb grows between three and five feet tall.
  • The feathery fennel foliage looks similar to dill.

Market for Herb Fennel

According to Growing for Market, fennel growers cultivate herb fennel for its leaves and seeds.

  • The different uses include soups, fish recipes, salads and teas.
  • Fennel seeds are used in baked goods, desserts and even drinks.
  • You can also use flowers, seeds and leaves for teas.

Vegetable Fennel

The vegetable fennel (Florence fennel or Finocchio – Foeniculum vulgare var. dulce) is usually referred to as Florence fennel or anise fennel due to its taste. There are countless recipes for vegetable fennel dishes.

  • Florence fennel is of the carrot family and produces a bulb-like vegetable.
  • Compared to herb fennel, vegetable fennel is shorter in height.
  • The fennel bulb is typically harvested before the plant blooms. You can always wait to harvest a few plants to allow the flowers to emerge and then harvest both at the same time.
  • Vegetable fennel seedlings are also grown as microgreens.

Grow Vegetable Fennel

Fennel is easy to grow and can be added to your garden plan. You can typically get two crops out of this bulb-shaped vegetable during most growing season zones. Once in the spring and again in the fall (harvest the second crop before first frost).

  • This annual vegetable has a maturation of 80 to 115 days.
  • Start seedlings indoors eight weeks before the last frost or direct sow three weeks before the last frost.
  • Plant 12 inches apart or one per square for a square foot raised bed garden.
  • Fennel requires rich, moist, well-drained soil.

Grow in Containers

You’ll probably want to select a smaller bulb fennel variety such as a Romanesco for a container garden.

  • Select a deep container, at least 12″ deep.
  • Use loose soil, such as potting soil or vegetable specific soil for containers.
  • Keep the soil moist at all times.
  • As the bulb grows, you’ll need to add soil to hill up the plant by covering the bottom leaves. You’ll need to repeat this as the bulb grows bigger.

Tips for Growing Perennial Herb Fennel

Perennial herb fennel is self-seeding and can be grown in hardiness Zone 4 and up.

  • A mature herb plant can yield as many as 100,000 seeds.
  • Growing one or two plants is usually sufficient for most families.
  • Don’t plant near dill to void cross-pollination.

Fennel Seeds

The seeds for both plants are oval in shape and fairly small.

  • The herb fennel is used for seed production.
  • You can use whole seeds or purchase fennel powder to use in various recipes.

Fennel Medicinal Uses

This ancient herb and plant have been used for centuries in various traditional medicines, such as Ayurveda to treat a wide range of medicinal conditions. Fennel has been used for reproductive, digestive, respiratory and endocrine related illnesses, including cancer, arthritis, colic, conjunctivitis and a long list of other diseases. All parts of the plants are used in these treatments. It has also been used to aid lactating mothers needing to produce more milk. Fennel chemical properties are being studied for the treatment of dementia and Alzheimer’s.

How to Use

You can get the benefits of fennel in a variety of ways.

  • Powdered fennel is often used in lieu of whole seeds.
  • Fennel tea can be used for medicinal or culinary purposes.
  • Fennel extract is also used for medicinal purposes.
  • In some cultures, fennel seeds are chewed at the end of a meal to aid digestion and prevent bad breath.

Other Health Benefits

Vegetable fennel is a healthy food to consume because it is high in fiber, Vitamin C and potassium. It also has iron, calcium, magnesium and other nutrients. Eating fennel can help bone health, improve skin health, aid in digestion and may be beneficial for eye health and blood pressure. In addition to the above medicinal uses, herb fennel may also be beneficial for menopause symptoms, and the compounds present in fennel may be potentially helpful in treating glaucoma and hypertension.

Herb Fennel Invasive Plant

Unlike Florence fennel, herb fennel can be invasive. Washington State University Extension (WSUE) warns that herb fennel can escape your garden and become invasive.The hardy fennel seeds are still viable even when dormant in the soil, and the taproot can grow 10 feet deep, ensuring the plant survives during droughts. As an invasive plant, it can crowd out native plant life.

Control Methods for Herb Fennel

There are a few things you can do to fight an herb fennel infestation. These include:

  • You can manually remove the flowers when they bloom to prevent reseeding.
  • WSUE advises to burn the plants for an effective countermeasure.
  • Herbicides can be used if hand-pulling, removing blooms and burning aren’t effective enough to eradicate the infestation.


An unrelated flower grown for its seeds, Love-In-A-Mist Flower (Nigella damascena) is often called Fennel Flower or wild fennel. This annual herb is native to southern Europe and North Africa. This plant is grown specifically for its seeds.

  • The plant foliage is the typical feathery fennel look.
  • The blossoms are a bright lacy blue, while some varieties produce pink, white or purples blooms.
  • Unlike the other fennel seeds, nigella seeds taste like nutmeg, and are used in wines and desserts.
  • This seed has no known medicinal value.

Fennel Flower’s Many Uses

The fennel herb and vegetable plants appear to be a treasure trove of possible benefits to humans. Both forms are easy to grow and may provide you with the diversity you seek in your garden.

Planting Fennel – How To Grow Fennel Herb

The fennel herb (Foeniculum vulgare) has a long and varied history of use. The Egyptians and the Chinese used it strictly for medicinal purposes and their lore was brought back to Europe by early traders. During the Middle Ages, it was believed to hold magical qualities and people hung fennel plants over their doors to drive away evil spirits. Eventually, someone recognized its use as a flavoring for eggs and fish. Today, its crisp anise flavor makes it a favorite of cooks everywhere.

Native to southern Europe, the fennel herb is now naturalized throughout Europe, North America and Australia and grown in gardens all over the world.

Planting Fennel

You’ll find two methods of propagation when researching how to grow fennel. Plants may be divided, but this isn’t as easy as it is with other garden plants and often proves unsatisfactory. Like their aforementioned cousins, the fennel herb has a long tap root that doesn’t like to be divided or moved.

Planting fennel by seed is the much easier option. Seed can be sown as soon

as the soil warms in the spring. Soaking your seeds for a day or two before sowing will ensure better germination. Keep the area moist until the seeds sprout and thin the fennel plants to 12 to 18 inches apart when they are 4 to 6 inches tall. Plants will begin flowering about 90 days after planting.

Growing Fennel

The steps for how to grow fennel are fairly simple since the fennel herb is such an agreeable garden plant. It belongs to the carrot and parsley family and is a cousin to other herbs such as caraway, dill and cumin. Like these other herbs, fennel plants produce aromatic fruits which are commonly, though incorrectly, referred to as seeds.

When growing fennel, choose a sunny location in the back of a well drained bed. The fine textured foliage can grow up to 6 feet tall and makes an excellent backdrop for other flower planting.

Fennel is a short lived perennial that blooms best in the second year. It readily re-seeds and while not considered invasive, it has certainly earned its reputation for aggressive growing. Fennel can be cut back early in the season to encourage bushier growth and should be deadheaded for seed harvest and to prevent over seeding of new plants.

Harvest and dry seeds as the flower heads fade. There’s only one restriction to how to grow fennel: don’t plant it near dill. Cross pollination results in strangely flavored seeds for both plants!

Once established, fennel herb doesn’t need much care. It prefers acid soil, appreciates the occasional dose of mild fertilizer and a little additional water if the weather is hot and dry.

In addition to its kitchen contributions, planting fennel will attract beneficial insects to the garden and its leaves are a favorite with the caterpillars of the swallowtail butterfly.

Whether grown for its culinary value or strictly as on ornamental, growing fennel herb will be an easy and attractive addition to your garden.

Why fennel is the gardener’s friend

As a herb, use stems and fronds to flavour any pork or fish dish. Bake pieces of meat or fish in foil in the oven packed with fennel ferns, and barbecue fish on a bed of stems for a really intense flavour. Use the seeds to make your own ras el hanout spice mix with garden lavender, bay leaves, fennel and cumin seeds, rose petals, nutmeg, cloves and peppercorns, roast then grind, to steep in oil, and then dip in chunks of crusty bread. Mix the roasted seeds with black, pink and white peppercorns and salt to make a delicious crust on baked salmon, or combine with chilli in dark chocolate.

Umbelliferae are decorative garden plants, both Foeniculum vulgare and its bronze relation will seed and squeeze in readily all over the border, without elbowing out their companions. Decorative cousins, the noble but inedible Ferula communis and tingitana ‘Cedric Morris’ are available from Great Dixter. Even the wildlife love fennel, especially the foliage beloved by swallowtail caterpillars (and slugs) and the flowers adored by hoverflies and all sorts of beneficial insects.

How to grow Florence fennel

Grow in moist, fertile soil in a sunny site.

Sow in open soil in rows when the soil is warm in late May/June.

Space to 12in/30cm apart, keep plants watered or they will bolt.

Earth up the soil as the bulb begins to swell, hopefully to the size of a tennis ball.

Cut off at ground level, the root will carry on growing, the sprouts are good in salads.

RHS recommended varieties ‘Perfection’, ‘Cantino’ and ‘Amigo’ are bolt resistant.

Late variety ‘fennel of Parma’ by can be sown in late July/August to be harvested early winter. Alpine fennel ‘fenchel’ also available.

Buy fennel from the Telegraph Gardenshop.

British food fortnight events

Horsham District Food and Drink Festival until Sept 29

The Big Harvest Weekend, Greys Court, Oxfordshire Sept 22

Autumn Food and Home Fair, Essex With demonstrations by Sophie Grigson, Oct 5-6

The Aldeborough Food and Drink Festival Sept 27-Oct 13

Aylsham Food Festival Sept 28-Oct 6

Norfolk Food and Drink Festival until Oct 6

Spalding’s Annual Pumpkin Festival Oct 1-7

Lincolnshire Game and Country Show Sept 28-29

Sheffield Food Festival Sept 21-22

Harvest Flower and Food Festival, Diseworth Oct 5-6

Marlow Food Festival Sept 29

London Urban Food Fortnight Sept 14-29

For more events around the UK, go to Love British Food

How To Grow Fennel

Foeniculum vulgare

A hardy, perennial European herb (Foeniculum vulgare) grown as an annual for its aromatic seeds and fragrant young leaves, both of which are used for flavoring.

In Florence or Sweet Fennel (var. dulce) the greatly enlarged leaf bases form a bulb-like structure 3 to 4 inches in diameter which is called the “apple”. When blanched by earthing up it is cooked as a vegetable, but the stalks, resembling anise-flavored celery, can also be eaten raw.

Growing the Herb Fennel

As the seed is slow to sprout, sow it early in spring. The plants require full sunlight but only the simplest culture in any good garden soil.

As the plants grow rapidly, make successional sowings two weeks apart.

Fennel propagates well by seed, but can also be propagated by root and crown division. The seed can also be planted late in fall. When well established, thin plants to stand 8 to 12 inches apart in the row. Plants can also be started indoors and transplanted to the field when 3 or 4 inches tall.

Growing Cultures

Outdoors, in containers (sow directly in growing pots, do not transplant), and hydroponic cultures.

Plant Height

Fennel usually grows to a height of 18 to 24 inches (45 – 60cm).

Plant Spacing

Fennel plants should be spaced between 9 and 12 inches (22-30 cm) apart.

Preferred pH Range

Fennel will grow in a relatively wide pH range between 6.1 (mildly acidic) and 8.0 (mildly alkaline) with a preferred range between 7.0 and 8.0.


From seed. Direct sow outdoors in fall or in spring after last frost, Fennel does not transplant well.

Seed Germination Period

Fennel seeds will germinate in approximately 8 to 12 days.

Number of Seeds per Gram

There are between approximately 200 and 300 fennel seeds per gram, depending on variety.

Soil Requirements

Fennel will grow well in well-drained, deep and moderately fertile soils.

Alternative Growing Media

Soilless potting mixes (Pro-Mix, Sunshine Mix, etc.), perlite, vermiculite, coco peat.

Time From Seed to Saleable Plant

Seed to saleable plant in ten weeks.

Sun & Lighting Requirements

Fennel grown outdoors prefers full sun.

Fennel will grow indoors satisfactorily under high output T5 fluorescent plant lights or high intensity discharge (metal halide or high pressure sodium) plant growing lights. Keep high output fluorescents approximately one foot above the plants, and HID lights between 2 and 4 feet above the plants, depending on wattage. Have an oscillating fan gently stir seedlings for at least 2 hours per day to stimulate a shorter, sturdier, and more natural plant habit.

USDA Hardiness

8a to 10b. Fennel florance grown as annual.

Water Requirements

Water regularly, being careful not to overwater. Allow soil to go almost dry between watering, then soak thoroughly.

Potential Plant Pests and Diseases

Fennel can be susceptible to aphids and damping off.

Companion Planting

Fennel is only beneficial to dill, and in fact is detrimental to almost every other plant species. Dill is one of a very few known plants that will successfully grow near fennel. Fennel attracts ladybugs, syrphid fly, and tachinid fly and repels aphids.

Special Notes

Fennel is known to attract bees, butterflies and birds. Suitable for containers. Fennel should not be planted near almost all plants, as it can inhibit growth, cause bolting, or actually kill other plants.

Buy Fennel Seeds by Botanical Interests

Heirloom Fennel Florence Finocchio Seeds
Sweet licorice flavored “bulbs” (90 days), and delicately flavored, feathery foliage.

Organic Fennel Florence Perfection Seeds
Larger, more uniform “bulbs” & delicately flavored foliage. Developed for cool, northern climates.

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

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.

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

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

Feed with a general granular plant food each spring.

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 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.

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.

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.

Flowering season(s)


Foliage season(s)

Spring, Summer, Autumn


Full sun

Soil type

Chalky, Clay, Loamy, Sandy

Soil pH


Soil moisture

Moist but well-drained

Ultimate height

Up to 1.8m (6ft)

Ultimate spread

Up to 1.5m (5ft)

Time to ultimate height

1-2 years

Lacy, beautiful fennel plants grace planter boxes and the delicate leaves are lovely in salads. Like dill and parsley, the flowers of fennel are intensely attractive to beneficial insects. Grow fennel in a sunny position in well-drained loamy soil. If your soil is on the clay side, add some sharp sand to the bed. In the first year, fennel will grow to about 60cm (24″) tall, but in mild areas plants can reach 2m (6′) tall. Follow these how to grow fennel instructions for perfect fennel every year.

Foeniculum vulgare
Family: Apiaceae


Season & Zone
Season: Warm season
Exposure: Full sun
Zone: Hardy to Zone 5

Direct sow any time after last frost to early summer. Fennel can be started indoors, but like its close relative dill, it responds to transplant shock by bolting. Peat, coir, or newspaper pots may help prevent this. Optimal soil temperature for germination: 15-21°C (60-70°F).

Sow seeds 1cm (½”) deep, a few seeds in each spot you want a plant to grow. Thin or space to 30cm (12″) apart.

Grow fennel in a sunny position in well-drained loamy soil. If your soil is on the clay side, add some sharp sand to the bed. In the first year, fennel will grow to about 60cm (24″) tall, but in mild areas plants can reach 2m (6′) tall.

Gather the fronds to use in salads and dressings. Use the seeds in baking. These plants will self-sow readily and become a weed if the seed heads are not removed in the fall.

Seed Info
Usual seed life: 3 years.

Companion Planting
Not a companion for any garden food plant, fennel will actually inhibit growth in bush beans, kohlrabi, tomatoes, and others. Plant it, but keep it out of the veggie garden.

More on Companion Planting.

The Greek nicknamed this memory-enhancing, cancer-inhibiting herb maratho, or “marathon,” based on its versatile uses—specifically to support longevity and strength. Fennel is a common plant that thrives particularly well in the Mediterranean and some areas of North America, Asia and Europe. It is used as both an herb, due to its medicinal properties, and as a vegetable, which can be eaten raw, stewed, grilled, baked or boiled. All parts of the plant are edible, including the seeds, roots, shoots, leaves, and bulbs.

According to the USDA National Nutrient Database, fennel is a significant source of vitamins A and K, phosphorus, sodium, potassium, and calcium. Fennel also contains small amounts of folate, which is known to inhibit cancer growth and protect from free radical damage. A recent study, examining the many benefits of fennel, notes that it is suited for pharmacological use and successfully treats over 40 types of disorders due to its phytochemical properties. Flavonoids, phenolic compounds, fatty acids, and amino acids compose the internal structure of this herb.

Growing Conditions for Fennel

Fennel is considered either a perennial or annual herb, depending on the region where you live. It grows best in temperatures that range between 21-24 degrees Celsius or low- to mid-70 degrees Fahrenheit. Early fall or late spring, after the final frost, are ideal times of year to plant fennel.

Despite its sensitivity to temperature, fennel can tolerate a wide range of soil pH, from 4.8 to 8.2. Fennel prefers well-draining soil that is rich in nutrients. If the soil is too dry, the bulb will bolt, or split. It should be planted in an area where there is plenty of room to space out the seeds that will allow six hours of full sunlight per day.

How to Plant Fennel

Most gardeners propagate this herb from seed, though you can purchase it potted and transplant to your garden. However, the University of Illinois Extension suggests that fennel does not transplant well due to its taproot system. Each plant needs a depth of at least one foot for the roots to grow if you choose to use a container.

The seeds self-sow easily, and plants often return every year on their own. Initially, seeds should be planted 12-18 inches apart in rows 24 inches apart. The plant can grow up to 6 feet tall and 2 feet wide, so it’s important that there is plenty of space for each seedling to grow.

Care of Fennel

It is imperative that the soil remain consistently moist. The best way to test the soil is by pressing your thumb or forefinger into the ground about an inch deep, and checking to see how dry it is. If the soil is too dry, the stalks will split. To create a bushier fennel plant, trim the stalks closest to the ground. New and more numerous shoots should then grow.

Garden Pests and Diseases of Fennel

Common pests that interfere with the health and growth of fennel include the following.

  • Aphids
  • Thrips
  • Larvae of swallowtail butterfly
  • Slugs and snails

Common diseases that can infect fennel plants include the following.

  • Cercospora leaf spot
  • Powdery mildew
  • Mycoplasma
  • Collar rot
  • Root rot

Harvesting Fennel

Fennel is ready to harvest just before its flowers bloom—typically three to four months after planting. It can need up to seven months for the base to swell enough to be ready to harvest and eat, though the leaves can be harvested at any time. To preserve the seeds, allow them to dry until the plant has turned a golden yellow, and then empty the pods.

Fennel Varieties to Grow in Your Garden

There are two main types of fennel varieties.

  1. Foeniculum vulgare, “herb fennel”
  2. Foeniculum dulce, “Florence fennel”

Both fennel breeds share the signature sweet, black-licorice scent that resembles that of the spice anise. Herb fennel is used more frequently for medicinal purposes, while Florence fennel is traditionally used for cooking. Most people prefer the white, fleshy bulb that the Florence fennel is known for, though it is harder to maintain.

Want to Learn More About Growing Fennel?

Writer Emily Nickles is a freelance writer and recent honors alumna of Texas Woman’s University. She was Editor-in-Chief of the student newspaper, The Lasso, for a year and was a page editor and reporter for three. Her senior year, Emily won the Sarah McIntire Award for Outstanding Capstone for her project titled The Lasso: A brief history 1914-2017.

Foeniculum vulgare and Foeniculum vulgare var. azoricum

There are two types of sweet fennel. The first is the common or herb type, Foeniculum vulgare, prized for the anise-like flavor of its feathery leaves and robust seeds.

The second is Florence or bulb style, which produces crisp celery-like bulbs bursting with anise-like flavor in addition to fragrant foliage and seeds. In my family, this vegetable has always been a holiday treat known by its Italian name, “finocchio.”

Would you like to grow them your veggie garden? Read on to for the details!

The Fundamentals of Fennel

Fennel is grown from the edible seeds that are produced after the flower blossoms fade. Here’s how to get started on your crop.

Sowing Seeds

This is a cool weather crop that matures best without enduring summer’s intense heat. Sow in early spring or late summer for best results.

In zones 6 to 10, you may grow it as a perennial or possibly biennial. However, it won’t withstand hard frost and grows in most places as an annual. In California, it has become invasive, so check its status in your region before you plant.

To cultivate varieties of F. vulgare, choose a location with full sun that is close to a water source. The soil should be organically rich and on the acidic side, so amend it with compost if necessary. You may want to do a soil test to evaluate your earth.

Sow seeds directly into the ground a few weeks before the last predicted frost date, or start them indoors about six weeks ahead of the growing season. Get a jump on germination by soaking them overnight so they sprout before placing them on top of damp soil. Tamp lightly to cover the seeds with dirt and maintain even, but not overly-saturated moisture.

You may try growing fennel in containers on a patio or balcony. Two things to remember here:

  1. The tap root is about a foot long, so you’ll need a deep pot.
  2. Pots dry out quickly, so be vigilant with watering.

Some folks believe that fennel and dill cross pollinate if planted in proximity to one another. Others pooh-pooh that theory. Keep this in mind, and see what happens in your garden!

As the first true leaves begin to appear, thin seedlings to about a foot apart from each other. Transfer seeds started indoors to the garden at this time. Let them acclimate to the outdoors by remaining in their seed starter pot for a day or two to harden off before transplanting into the garden at one-foot intervals.

Ideally, bulbs mature before flower buds appear. You won’t get blossoms or seeds if you harvest the bulbs, but the vegetable will be at the peak of sweetness. Starting seeds indoors is one way to hasten the process.

Nurturing Your Crop

Bulb-less plants in green and bronze varieties may reach five feet in height, forming a texturally-rich backdrop of feathery leaves in borders and beds. Keep the soil evenly moist as flower heads of tiny yellow blossoms appear, followed by fragrant seeds.

Bulb varieties may reach three feet tall as fine, dense leaves form and the vegetable begins to enlarge. Once you see swelling, mound dirt up around the bulb to protect it from sunburn. This technique is called “blanching.”

Adding mulch over the top of the bulb-like roots of the Florence varieties ensure that they remain white and more satisfying in culinary endeavors.

Continue to water regularly but avoid over-saturation and the ponding of water to prevent rotting. You may fertilize lightly during this time.

To get the best bang for your buck, snip the ends of the foliage before they begin to bud for exceptional bulb development. Preventing the formation of buds – and hence, seeds – is also an excellent way to curb the invasive tendencies of the plant.

In areas where summer heats up quickly, you may be better off planting mid- to late-summer for a fall crop. If you should have a particularly warm spell, plants may “bolt” or suddenly go to seed, and maturity comes to a grinding halt. Foliage and blossoms may be usable, but immature bulbs may be a loss.


Delicate and delicious foliage and blossoms may be harvested throughout the growing season for use in salads, and as attractive garnishes. You may even pick the tender young shoots of seedlings to eat as tasty microgreens.

The rule of thumb here is to harvest bulbs when they are about tennis ball-sized. Slice each off cleanly at ground level with a clean knife, and slice the elongated stems and profusion of leaves off at about three to six inches above the bulb. All parts are edible.

I like to slice the bulbs thickly and store them in an airtight container with a little water in the fridge. Each morning I change the water and they last for three days. After that, they start to turn brown on the edges.

Alternatively, you may place whole vegetables in an airtight plastic bag in the refrigerator for about a week. Foliage tops and stems may also be stored in an airtight plastic bag in the fridge for up to a week. Wash before serving.

Read more about storing and using fresh fennel .

Dry seeds should remain robust and aromatic for several years when stored in an airtight jar.

Foodal also has some great ideas for using the seed for flavoring in your cooking.

Diseases and Insect

You should have few issues with F. vulgare in its various forms. Aphids or white flies may occasionally be a nuisance, but provided you don’t over- or under-water, all should be well. One visitor you may have is the parsley worm.

This little guy is the caterpillar stage of the black swallowtail butterfly. You may pick him off, or decide to share some foliage, as it is a beneficial garden pollinator.

Where to Buy

Florence variety seeds are available from Burpee.

Florence Bulb-Style Fennel via Burpee

Orion hybrids are also available from Burpee. You may buy a 100-seed packet or a set of three plants. This compact type is less susceptible to tip burn than others, and it matures in 80 to 85 days.

Orion Hybrid Fennel via Burpee

Bulb-less Bronze-type seeds are available from True Leaf Market.

Bonze Leafy Fennel via True Leaf Market

Even without the vegetables, the leaves are beautiful in the garden and delicious on the table. Blossoms produce seeds that may be dried for culinary use.

Recipe Ideas

Organic Brussels Sprouts Sautéed with Bacon, Fennel Seed, and Dill

If you’ve never like Brussels, then you haven’t tried them al dente, cooked with bacon, and flavored with the taste of fennel and fresh dill.

Besides the incredible flavor, the fat from the bacon allows fat-soluble nutrients to absorb more easily into the body.

Get the recipe now on Foodal.

Balsamic Tomato & Fresh Fennel Sauce for Bruschetta

Are you looking for an easy, no-cook sauce to make a quick crostini or bruschetta? Try this tasty recipe, prepared with fresh fennel and cherry tomatoes.

You can also serve this tasty sauce on top of pasta, spiralized veggies, or anything you would usually serve with marinara.

Find the recipe now on Foodal.

Fennel Nettle Iced Tea

Do you love a good healthy tea?

This fennel nettle iced tea blend is naturally sweet and has powerful natural benefits. It’s a tasty take on a ubiquitous beverage, with unique flavors.

Find the recipe now on Foodal.

Flavor and Versatility

Now you have to low-down on sweet fennel varieties. If you love the crunch of celery, and the licorice-like flavor of anise, this healthy herb/vegetable is going to be the star of your garden and your table this season.

Some folks like to dry the seeds to use as seasoning. Others chew or brew them as a digestive aid. And the pollen – oh, the pollen! It imparts a concentration of flavor you just won’t believe.

Try growing fennel in your herb garden this spring!

And if you’re a fan of growing herbs, you’ll love some of our other growing guides:

  • Add Some Spice to Your Life: Grow Your Own Horseradish
  • Parsley: The Wonder Herb That’s Easy to Grow
  • Summer Savory: The Peppery, Piquant Love Herb


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© Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Product photos via Burpee and True Leaf Market. Uncredited photos: .

About Nan Schiller

Nan Schiller is a writer with deep roots in the soil of southeastern Pennsylvania. Her background includes landscape and floral design, a BS in business from Villanova University, and a Certificate of Merit in floral design from Longwood Gardens. An advocate of organic gardening with native plants, she’s always got dirt under her nails and freckles on her nose. With wit and hopefully some wisdom, she shares what she’s learned and is always ready to dig into a new project!

Florence fennel is a cool-weather perennial grown as an annual. Fennel can be sown in the garden as early as 2 to 3 weeks before the average last frost date in spring. Florence fennel, which is grown for its bulbous stalk, requires 90 to 115 frost-free days to reach harvest. For an autumn crops sow fennel in mid- to late summer.

Description. Florence fennel or finocchio is grown primarily for its bulbous base and leaf stalks which are used as vegetables. Fennel is a stocky plant that can grow to 24 inches tall and looks something like celery with fleshy stalks and feathery leaves. A taller cultivar of fennel known as common or sweet fennel is grown for its leaves and seeds which are used as herbal seasonings. Fennel produces a flat-topped cluster of small, golden flowers. Both Florence fennel and common fennel are members of the parsley family.

Yield. Plant 5 Florence fennel plants for each household member.

Planting Florence Fennel

Site. Grow fennel in full sun. Plant fennel in well-drained soil rich in organic matter. Prepare the bed in advance by working in aged compost. Fennel prefers a soil pH of 5.5 to 6.8.

Planting time. Florence fennel is a cool-weather perennial grown as an annual. Fennel can be sown in the garden as early as 2 to 3 weeks before the average last frost date in spring. Seeds germinate best at 60°F. Fennel will tolerate heat and cold but does best when it comes to maturity in cool weather. Fennel requires 90 to 115 frost-free days to reach harvest. For an autumn crop sow fennel in mid- to late summer.

Planting and spacing. Sow fennel seed a ¼ inch deep 4 to 6 inches apart. Thin successful seedlings to 12 inches apart. Space rows 24 to 36 inches apart.

Companion plants. Mints and members of the mint family.

Container growing. Florence fennel will grow in a 6-inch pot; in larger containers grow Florence fennel on 8-inch centers. Spring plantings will not produce a large bulb. Plant in fall so that the plant comes to maturity in cool weather.

Florence Fennel Care

Water and feeding. Keep fennel on the dry side; the soil should be evenly moist but not wet. Mulch to retain soil moisture in hot regions. Prepare planting beds with aged compost. Side dress fennel with aged compost at midseason.

Care. Blanch the lower stems when the bulbous base grows to the size of an egg; do this by mulching up around the bulb–the bulb will be more tender and sweet at harvest. Remove seed stalks to increase the production of stems and bulbs. Fennel will self-seed if left unattended.

Pests. Fennel may be attacked by the parsley caterpillar. Remove it by hand. Generally, fennel has no other serious pest problems.

Diseases. Fennel has no serious disease problems.

Harvesting and Storing Florence Fennel

Harvest. Fennel’s bulbous stalk can be harvested when it is 3 inches or more in diameter. Cut the whole stalk like celery just below the point where individual stalks join together. Cut leaves as needed once they have reached 18 inches tall. Florence fennel will be ready for harvest 90 to 115 days after sowing. Common fennel sprigs can be cut for flavoring once the plant is established.

Storing and preserving. Fennel is best eaten fresh. Florence fennel will keep in the refrigerator up to 1 week or in a cold moist place for 2 to 3 months. Stalks can be frozen or dried. Fennel leaves can be frozen or dried as herbs; dried leaves should be kept in an airtight container.

Florence Fennel Varieties to Grow

Varieties. ‘Hearld’ for spring planting. ‘Zefa Fino’, ‘Rudy’, and ‘Trieste’ have large, flavorful bulbs.

Common name. Fennel, Florence fennel, finocchio, fenucchi

Botanical name. Foeniculum vulgare dulce

Origin. Mediterranean


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