Home » Herbs » Planting, Growing, and Harvesting Fennel.

Planting, Growing, and Harvesting Fennel.

Growing fennel, Fennel belonging to the carrot family, is a flowering plant species. They are one of the hardiest perennial herbs cultivated across the globe. The plants find their origin on the shores of the Mediterranean.

The distinctive yellow flowery couple with feather-like leaves makes them a treat to the eyes. The plant prefers a soil that is dry and found in the coastlines and banks of the river. The herbs find themselves in use in various dishes across various cuisines due to their aromatic nature.

Biological Name

Foeniculum Vulgare.

Plant Type

Herb type.

Maturity Period

They take about 90 days to mature.

Maturity Size

They can reach a height of about 6 feet.

Soil Type

They prefer soil that can hold moisture in them along with a sound drainage system

Soil pH



They prefer full sun but can grow in shades as well.

Hardiness (USDA Zone)

They lie in the 6-10 range.


A distance of about 4-6 inches between two plants and 18 inches row to row proved to have generated desired results.

Bloom Time

The plants start blooming with the onset of summer and last till the first frost date.



Flower Color

The flowers on the fennel plant come in yellow color.

Growth Rate

The plant takes about 90 days to mature and become ready for harvest.

Native Zone

They are native to the Mediterranean regions.


Routine watering of the plant to keep the soil moist helps the plant to grow well. The plant loves a soil rich in potash fertilizers and fertilizes the soil every three weeks till the plant establishes. The weed growth can become a problem for the plant, so special attention is required to handle the situation.


The use of fennel seeds for medicinal and culinary purposes can get considered well-known to all.

Many people may find it surprising to learn that people believed in its magical power to keep evil out of their homes in many cultures. People used fennel seeds to treat snake bites in ancient China, while the Egyptians held the herb high for their medicinal powers. The origin of the marathon is related to the fennel.

Many people believed ancient Athenian Pheidippides took a fennel stalk while completing his run of 150 miles to Athens as he tried gathering soldiers for the battle of Persia 490 BC.

People believed consuming fennel tea in ancient Greece gave their soldiers the courage to fend off their enemies. According to the Greek mythologies, while carrying fire from Olympus to earth, Prometheus used a giant stalk of the fennel plant.

Nutritional Facts:

Both fennel herbs and seeds got packed with nutrients that help the human body perform optimally.

The low-calorie content coupled with a rich source of Vitamin C makes it a necessity in every person’s diet. The Vitamin C present in the fennel helps the body to repair and fight against various diseases.

They help the body to recover from tissue damage, improvement in the immune system and synthesize collagen. The manganese content of the fennel herb plays a vital role in activating various enzymes, regulating the glucose level in the blood, and developing bones.

The different other minerals, along with manganese, help the body by providing potassium, magnesium, and calcium. The antioxidant-rich fennel seeds help the body neutralize free radicals in our body that directly impact premature aging and various other ailments.

The Fennel herbs are rich in plant compounds, and approximately 80 types of them are available in the essential extracted from it. Polyphenols in the extracted essential oil help the body with the needed anti-inflammatory agents to fight various problems.

Nutrients and Minerals for Fennel:

Fennel plant often gets considered as one of the heavy feeder variants of crops. The need to add fertilizers to the soil directly affects its growth and eventual establishment. The plant prefers soil rich in nitrogen to grow well.

Cultivators should go for a soil test before adding any fertilizers to the earth. The soil test reports always give a clear picture regarding the soil pH and minerals in them. NPK fertilizers with high nitrogen content can become the best bet for growing fennel.

A ratio of 21-0-0 will provide the plant with the needed nutrients for it to grow and thrive. However, cultivators should pick slow-releasing fertilizers before sowing the fennel seedlings into the soil.

After three weeks, the cultivators should shift to the NPK fertilizers. Watering plays an essential role in the fertilizers as it helps them mix well in the soil. The soil texture for fennel plants should always remain moist and strict monitoring should get carried out to keep the soil wet.

A general rule followed when watering the fennel plant involves adding 1-2 inches of water every week. People taking an organic approach to cultivation can go for a well-rotted organic matter like farmyard manure to fertilize the soil designated for fennel. The organic waste should go into the ground at least six weeks before the day of sowing fennel seedlings.

Adding mulch to the soil helps the soil retain moisture and adds bits of nutrients to them. Once the fennel bulb matures, cultivators should start adding NPK fertilizers once every two weeks until the plant becomes ready for harvest.

When to Plant Fennel:

While planting fennel, cultivators should keep a close eye on the temperature of the soil as fennel plants thrive in temperatures ranging from 60-90 degrees F. 

Ideally, once the last frost date passes, cultivators can start sowing seeds into the soil with ten seeds every foot and maintaining a spacing of about 18 inches. When sowing fennel seeds, the earth should always remain wet, and in case it feels dry, water the soil thoroughly.

A cover of about 1/8 inches of soil on the sources helps them to germinate quickly. Approximately, it takes about 7-10 days for the seeds to germinate. Soaking the seeds in water overnight helps to achieve quicker germination.

Bulbs fennel can go to the soil 3-5 weeks before the last frost date, as they may bolt when there is a chance of extreme frost. The bulb fennels can neither withstand very high heat nor intense frost when the soil temperature drops to 28 degrees F.

How to Plant Fennel:

The appropriate spacing helps the plant grow unrestricted and thinning the plant once the plant reaches a certain helps the cause. Soaking the fennel seeds overnight before sowing them in the soil helps the plant to germinate early.

A thin layer of soil on the sowed seeds allows the plant to grow faster and fennel seedlings to appear early. The taproot of the fennel plants does not like disturbance while growing sp transplanting them from one place to another always carries a risk.

However, people often sow seeds in the container and once it reaches a particular height transplant them to the soil. Using plugs or modules while transplanting minimizes the disturbance to the roots, helping the plant survive transplant shock.

The bulb fennel grows best when sowed in the mid to late summer as they become ready for harvest in the autumn. The bulbs can survive light one or two touches of frost, unlike the plant emerging from fennel seeds.

Where to Plant Fennel:

The plant requires direct sun every day during its growth phase to establish well. So, cultivators should pick a spot in the garden that receives ample sunlight during the daytime.

The soil for the plant should have a pH, not more than 6.5, and the earth should possess a sound drainage structure. The plant prefers soil that remains moist all the time, so adding mulch may help the cause.

A dark soil rich in organic manure can become the best bet when growing a fennel plant. Blanching the lower stem when the bulb becomes the size of an egg helps the plant to thrive and fetch more harvest at the end of the season.

Fennel Plant Care: 

The fennel plant care involves a series of simple steps that can fetch a good harvest at the end of the growing season.

The plant prefers soil rich in organic matters with a sound drainage system. The earth should remain moist at all times of the day, so adding mulch to the plant will not help the ground retain moisture but also provide the plant with the needed organic element for its growth.

A good six hours of sun exposure helps the plant grow voraciously and fetch sweet fennel during harvest. When maintained, a spacing of 12 inches gave each fennel plant the needed space to grow correctly and spread its roots.

Feeding fennel plants with water-soluble plant food will significantly improve the fennel leaves growth by few folds. Once the plant starts to bloom, cultivators can pinch off the top to prevent flowering and promote further development, giving the plant a much fuller and compact appearance.

Harvesting and Storing Fennel:

The method of harvesting varies from one variant to another. The herb fennel can become ready for harvest by cutting the foliage from the plant.

The vegetation, once harvested, can remain suitable for consumption by drying and improving its life expectancy. Harvesters looking for seeds to harvest should for the plant to flower, and once it turns brown, they can become ready for harvest. On the other hand, Vegetable fennel becomes ready for harvest once the bulb reaches up to a size of a tennis ball.

After digging a hole, the bulb gets removed from the soil, with the top of the plant chopped off. Once harvested, the bulb can remain fit for consumption when stored in a cool and dry place.

Types of Fennel:

Broadly, two types of fennels get cultivated across the globe:

  1. Herb Fennel
  2. Vegetable Fennel.

Now, the two variants have several other sub-varieties that fall under them:

  • Herb Fennel: The mentioned variant gets cultivated for its sweet seeds and is often called sweet fennel. They mostly find it helpful in adding flavor to the food. They bloom in the late summer, and their harvesting involves leaves, stems, and seeds.
  1. Sweet Fennel: Mostly find its use in culinary purposes.
  2. Rubrum: They are known by bronze fennel in different parts of the globe and harvested for the leaves. They find its use in the ornamental sector and some cases in culinary as well.
  • Vegetable Fennel: They get known by various names in different parts of the world like Finocchio, anise fennel, and many more. They have a bulb-like appearance with thick rosettes at the base. They find its use in numerous recipes of worldwide cuisines.
  1. Rhondo
  2. Cantino
  3. Victoria

Pests and Diseases of Fennel Plant:

  • Leaf Blight: They mostly attack the older leaves of the plant in January. Small necrotic spots start appearing on the lower parts of the plant. They take significantly less time to progress, and the areas become more prominent in size with a white erumpent growth on them.
  • Leaf Spot: They attack the older foliage, and the infected leaf tips and stems color changes and becomes brown to black. Eventually, the infected area starts to dry up and leads to eventual death.

Fusarium Wilt: The infected plant starts to wilt and finds new fennel seedlings and older foliage. They turn the plant yellowish, and mainly, they occur in plants that grow from infected seeds. 



  • Tangy Brisket with Fennel and Herbs.
  • Spiced Roasted Pork with Fennel and Apple Salad.
  • Collard Green Salad with Fried Plantain and Sumac.

Where does the fennel plant grow best?

Fennel plant grows best in soil that has a pH of not more than 6.5. They prefer soil rich in organic matter and sound drainage systems. The plant prefers soil that retains moisture and a garden area that receives sunlight for at least 6 hours during the day.

What should not get planted near the fennel plant?

People cultivating other crops and fennel should keep them away from plants like carrots with similar root structures.

Will fennel survive winter?

Fennel thrives in an area that has cool climatic conditions but cannot withstand a heavy frost. So, the cultivator always sows the seeds after the first frost date passes for the plant to survive.

Is fennel easy to grow?

Fennel plant requires very low maintenance as the soil needs fertilizers every three to four weeks gap.
The water demand, when appropriately met, helps the plant to grow properly and mature early.

How deep does the soil need to be for the fennel?

People growing fennel in containers should go for a container with a depth of about 12-14 inches.
The plant’s taproot requires a thick layer of soil to grow, and spacing between two plants should remain in the range of 18 inches.

Does fennel need full sun?

The fennel plant requires at least six hours of direct sunlight for the plant to thrive. They prefer a cool temperature, and 70 degrees F can get considered as an optimal temperature.

How long does it take for the fennel to grow?

The cultivators need to wait for about 90 days to mature and become ready to harvest fennel.

Does fennel need fertilizers?

Being a heavy feeder, the fennel plant requires a fertilizer rich in nitrogen as the mineral helps them establish quickly. Water-soluble NPK fertilizers help the plant to grow when fennel seedlings start appearing.
However, cultivators should add slow-releasing nitrogen fertilizers six weeks before the day of sowing seeds.  

Does fennel reseed itself?

Fennels of leafy variants can reseed themselves every season without any effort from the cultivator’s end. In contrast, the bulb-type fennel cannot get reseeded and needs sowing every season for the autumn harvest.

What month do you harvest fennel?

Ideally, autumn can become the harvest month of the fennel seeds.

How do I harvest fennel from my garden?

People growing fennel bulb can harvest once it reaches the size of a tennis ball. They need to uproot the plant and cut the bulb from the base. While in case of leaf fennel, cultivators can harvest the flowers once it turns brown.  

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