How To Grow Fennel Bulb

Grow fennel bulbs, at home, indoors, and outdoors, just follow these ‘how-to’ steps.

Bulb fennel, also known as Florence fennel or finocchio, is a herb native to southern Europe that was first used strictly as medicine but became a popular addition to meals later on. Its anise flavor is bright and recognizable and is perfect for seasoning fish, stews, and salads.

Growing fennel at home is easy, just follow these 7 simple steps to have a fresh supply of bulbs and leaves in your garden.

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Details for Growing Fennel Bulb

Planting MonthsEarly spring, June, early fall
Harvest Months3 months after sowing
Temperature to Plant60 F +
Planting Depth1/2 inch
Spacing9 – 12 inches
Sunlight8 +
DirectionNorth to south
DrainageMoist, but well-drained
pH Level6.0 – 8.0
Companion PlantsNone – keep separate
Health BenefitsAnti-inflammatory, soothes the stomach, rich in vitamin c, potassium, and calcium
Details for Growing Fennel Bulb

Seven Steps to Growing Fennel

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Fennel grows best in rich soil with plenty of moisture and good drainage. It tolerates a wide range of pH levels – from 6.0 to 8.0, but it is best to choose a soil with a neutral pH (closer to 7.0).

It will survive in worse conditions, but it would be best to add a hearty amount of compost and a bit of fertilizer on soil poor in nutrients to ensure a healthy crop.

Soil pH Testing 

You need to make sure that you accurately test your soil to give your plants the best chance.

Fennel, like many herbs with long taproots, does not handle being transplanted well. It should be sowed directly into the ground raked and cleared of weeds. Soak the seeds for a couple of days for better germination and plant them 1/2-inch-deep 4 to 6 inches apart from each other in a sunny spot.

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Spacing and Depth

After seedlings grow up to be several inches tall, thin fennel out for the plants to be 12 inches apart. It is better to prepare 8-inch tall raised beds for planting fennel because it will give its root more space to grow.


The best way to germinate your seeds so that they have a great start is with a germination kit. Seeds that are grown this way produce greater results.

Sowing should be done either in spring if the ground temperature reaches 60 degrees in your home area or in midsummer. Spring crops produce big, fragrant leaves, but smaller bulbs, whereas summer crops will give you fat, tasty bulbs.

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Be warned – fennel sowed in spring is more likely to bolt! Fennel can even be sowed in early fall if the winters are not too harsh because it is best for the plant to mature during cooler periods.

Companion Plants

It is not advised to plant fennel near other plants aside from dill (which has similar properties), because it will inhibit their growth, cause bolting, or even kill them. However, some gardeners say that crossing fennel and dill will result in terrible flavors of these herbs.


As to growing fennel inside the home, a single plant can be grown in a 6-8 inch pot, but it will not produce as big of a bulb as those planted outside.

The soil must have enough moisture, however, over-watering fennel will cause its taproot and the bulb to rot. Be sure to keep the ground moist but not wet. In hot, dry regions place mulch or grass cuttings on the ground around the herb – this will help retain the moisture in the soil.

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Preparing beforehand and mixing soil with aged compost before planting fennel will also help you in this regard.


Parsley caterpillars and slugs are the pests that attack fennel most frequently. These insects can be removed by hand or repelled using beer traps or eco-friendly slug pellets. Fennel also attracts swallowtail butterflies that will lay eggs on the plant but will not harm it otherwise.

Remove these insects, too, and place them on wild Queen Anne’s lace plants instead of killing them off.


When it comes to diseases, fennel is susceptible to getting root rot if the herb is waterlogged. Make sure the soil has good drainage to avoid it.

Increase Fennel Yield

To produce more tender bulbs, earth fennel up by pushing loose soil against the stem bases, just like you would do with potatoes. It will also help the plants be more stable during strong wind. Spray fennel with high-nitrogen fertilizer a couple of times just as it begins to bulb to grow bigger bulbs.

Fennel Size

When the stalks growing from the bulbs reach more than 3 inches in diameter, fennel can be harvested; the growing period can take up to 3 months. Don’t let the bulbs get bigger than the size of a tennis ball, because then the plants will bolt and become bitter.


To harvest fennel, its stalk should be cut off right below where it is divided into smaller stalks. Leaves can be cut when they are 18 inches tall – just cut as much as you need off with scissors or pinch them off with your hands.

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Fennel is very fast to flower and seed, so you have to be fast to harvest its foliage and bulbs. But don’t worry – the seeds themselves are used in culinary as well.


One of the issues people have is that their crops produce all at once. The best way to overcome this is with a dehydrator so you can store your food for years and the flavor is amazing.

Drying Seeds

To dry the seeds, wait for the flowers to turn brown and spread the seeds on a tray or a window screen. Keep them in a dry, warm place for two weeks, and make sure to look out for mice that will want to steal them. After drying, store the seeds in a dry, cool place for a couple of years.


It is best to use fennel fresh. However, if you want to store it, you can keep it in the refrigerator for up to 1 week or in a cold basement with moist air for a couple of months.


Bulbs and stalks can be either frozen or dried, as can be leaves, after which they should be kept in an airtight container.


Bulb fennel is a great source of calcium, vitamin C, and potassium. It is versatile in the kitchen and can be eaten raw – this way it will stimulate digestion and reduce inflammation. Its juicy stalk can be used like celery when cooking main dishes, and its leaves will be perfect as a fish seasoning.

The seeds can be used to brew stomach-soothing tea, aid that reduces bloating after eating broccoli and cabbage, and as an interesting twist in baking and cooking desserts.

Follow the steps above to grow your own crop and have fresh, fragrant fennel at your home!

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