Those that grow fennel (Foeniculum vulgare) in their garden will be rewarded with a myriad of pollinators including butterflies and bees, as well as beneficial insects like lady bugs. Fennel is native to Europe and it looks a lot like dill, which makes sense since they are related. Egyptians and Chinese used fennel medicinally.
This culinary herb, native to the Mediterranean, pairs exceptionally well with fish. It can also be added to salads, coleslaw, potatoes, eggs, stews and other types of meats. Some people like to eat it raw, but it has a very strong anise / licorice taste. So raw consumption of fennel may not be for everyone. Most people prefer to cook it, which makes it softer in taste and texture. It goes from crunchy and bold to mild and sweet. All parts of the plant are edible, including the bulb, stalks, leaves, flowers and seeds.
Fennel Growing Conditions
This herb is a perennial in USDA zones 6 and above. It can be grown in zones 5-10. However, many gardeners grow it as an annual since it doesn’t last long. Fennel blooms better its second year. Remove the flowers if you do not want your plant to self sow and grow more fennel in the same place next year. This herb is not considered an invasive specie, but it is quite aggressive.
Once your plant begins to flower it won’t put energy into growing a bulb. Some varieties of fennel do not bulb, so make sure to know which variety you have planted. If your bulbing variety hasn’t produced a bulb, this may be because it’s too hot and fennel may bolt in high temperatures.
Grow fennel in an area that receives full sunlight. This herb prefers acidic soil with a pH between 5.5 and 6.8. Soil should be well drained. Fennel needs to be watered regularly until it is well established since it needs a good amount of moisture. Once the plant is big, it can tolerate a bit of dryness.
Apply compost around the base of your plants every few months or compost tea once per month. Mulch around your plant to keep the weeds from growing.
Fennel does not like being next to most vegetables and some herbs; it is quite a solitary plant. Fennel is allelopathic, which means it releases chemicals into the soil which limits the growth of other plants. Do not grow fennel next to beans, tomato, peppers, wormwood, and kohlrabi. Cross pollination with dill or coriander can result in a strange flavor for both plants. Cucumber and nasturtium are good companion plants for fennel. This herb can be grown in containers to prevent problems.
How to Grow Fennel from Seed
Those who grow fennel should know that this plant doesn’t like to be transplanted. So, direct sowing is the best method. Fennel can even handle a bit of mild frost, so there is no need to wait until the threat of frost has past. Use a frost cover to protect young plants.
If you do decide to grow fennel indoors, then you can sow two or three weeks before the last frost. Soak your seeds for a day or two to ensure the best germination. Fennel seeds will germinate in 8 to 12 days. Keep your seedling tray moist until they sprout. Place them by the window in a warm area so the soil temperature is between 60-90 F (15-32 C).
Transplant when seedlings have two true leaves, which should be between four to six weeks after germination. But before you do so, make sure to harden them (take them out for a few hours per day) for a week before putting them on the ground. Flowering will happen about 90 days after you grow fennel.
It is important to plan when growing fennel since this herb grows pretty tall, up to 5 feet. Space your plants 12-18 inches (30-45 centimeters) apart in rows that have space of 2 to 3 feet.
How to Regrow Fennel
It is quite easy to grow fennel that was purchased in the supermarket or produce market. Just make sure to leave the base, where the roots grow from, intact when you cook with this herb. You should also leave a little bit of the bulb attached. To grow fennel from your old bulb, you simply need to place it in a shallow dish with water with the base facing down. Place it by a sunny window and change the water every few days so your fennel does not get moldy or rot.
New green shoots will start growing in a few days. Eventually new roots will sprout from the base. You can continue growing fennel it in water, just make sure to keep on changing it. Or you can place it in a deep container with well-draining soil.
Fennel can also be divided, but it is not as easy as other plants because this herb has very long tap roots which don’t like to be moved. Use a shovel to slice down the taproot vertically while inflicting the least amount of damage possible. It is best to do this early summer. Place the propagated fennel in a new hole and cover with soil.
Fennel Pest and Diseases
Caterpillars
When you grow fennel you are very likely to find caterpillars (parsley worm) eating your plant. These are usually swallowtail butterfly caterpillars which like to eat plants in the same family including dill, parsley and carrots. Those that don’t want to kill them can simply move them to other parts of the garden. They are pretty caterpillars and even prettier butterflies.
Mildew
Powdery mildew and downy mildew are two conditions to look for when you grow fennel. Both types of fungus look like your plants have powder on their leaves (downy also has yellow and with patches on top). Remove at first sign and spray with copper to control it. Destroy plants if this fungus is too advanced since it can spread to other plants.
Aphids
Aphids attack almost all plants. Blast them off with water and spray neem oil.
How to Harvest Fennel
Harvesting can happen in three months after you start to grow fennel. Harvest the fronds by clipping off the top part of the plant, which will encourage new growth. Do not harvest more than one third of the plant at once.
Once the plant has matured, you can harvest the bulbs by pulling them from the ground. These unwashed bulbs will keep in the fridge for about a week. Store the fronds separate from the bulb. Keep stems with leaves in a glass water on the counter so they last longer.
Those that want to get fennel seeds can pick off the seeds when the flowers have turned brown. Wrap them in cheesecloth to catch the seeds before they reach the ground.