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Growing The Herb Fennel In The UK

Growing fennel is a nice way to ensure you have a ready supply of an otherwise hard to find herb.

Fennel as a herb is grown as a perennial and although closely related to the Florence Fennel which we would eat the bulb from it has differences. We can use the gorgeous flowers in arrangements and as a perennial we can gather the seeds for eating and making teas. The flowers will also encourage the good bugs into your garden.

With so much of benefit to growing your own herb fennel, let’s look at how to do it!

How To Grow Fennel From Seed

We think you will love this simple way to grow fennel. The reason being you have the most amazing aniseed aroma as soon as you open the packet of seeds! We will be harvesting seeds in the future to eat so it is a nice early reminder of the benefits!

Soak your seeds for a few hours before sowing. I would recommend an overnight soak. We always seem to get great germination rates from this method, but just be aware that you will get 100’s of seeds in a pack and herb fennel grows to around 6 foot high!

Sow indoors in biodegradable plant pots. We use these as the roots do not like to be transplanted. By using biodegradable pots we can start them early in the season indoors, between March and May, then transplant them without affecting the root system.

You can sow directly to the ground, where they are to grow once the last frost has gone. In the UK that can be a bit of a worry, so keep an eye on that weather forecast! Use a cloche if needed.

We sow our seeds under cover and use a heated propagator if we have a gloomy start to March.

Use a compost that has plenty of rich humus and is peat free. When planting out prepare the soil with some well rotted compost from your own heap. Fennel can grow in pots and if you take this route, make sure to have enough space and drainage for this statuesque herb!

fennel grown indoors

You can purchase Fennel as a plant or seeds from Suttons online nursery or you can purchase Fennel seeds from amazon.

Fennel will be ready to plant out or sow directly from around mid May, as long as the evil frosts have passed (I am writing this in mid May and the frosts are being sneaky this year!)

When you sow directly you will be covering lightly with soil, so a shallow drill will be adequate. You will need to think about sunlight as the herb loves a full day of sunlight, but also requires good drainage. Space the seeds about 8 inches apart, you will need to thin to around a foot apart once the plants are around 6-10 inches in height.

When you plant out, keep space in mind. Fennel will grow to an architecturally pleasing 6 feet in height. It has a long tap root to go with this meaning that it is essentially drought tolerant, choosing instead to store water from a much greater depth than with other plants.

When putting fennel into a container think about a passive watering system. You can wait to water until the soil is dry, but do not be tempted to over water!

Caring For Young Fennel Plants

The main worry that you will have is protection from slugs and snails. The tender leaves are very tempting and although drought tolerant as an adult plant, the young seedlings will need to be kept in moist soil, this makes them ideal candidates for those little munchers. We had a few destroyed this way.

To deter slugs and snails try egg shells, wood shavings or straw around the base of the young plants. You can also try beer traps but we would not recommend chemical intervention. This is because we want a garden that the whole family can enjoy and we like our small humans to be able to eat as they garden.

A good two for one is a cloche. It protects from frosts and when it is too windy and rainy, but also affords a degree of protection from the evil slugs.

Aphids can also be an issue. They are keenly farmed by ants who will then feast on the honeydew that they excrete. This can kill off younger plants as the honeydew encourages black sooty molds.

To recover from this introduce ladybirds as a natural predator, or pinch the aphids and rub them off from your younger leaves. Once the plants have established they release their essential oils and are a natural remedy to many pests in the garden.

Make sure to keep the area well weeded as younger plants can easily be drowned and have all of their resources taken by invasive plants.

Be very aware of cross pollination with dill. You may think that the two are very similar in flavour and aroma, however when they mix you get a very disappointing result and it will always mean a loss of taste and general lack of vibrancy.

fennel in situ
fennel is a family favourite and can be a great herb to grow for kids.

About 90 days after sowing you will find that the plants start to flower. So they are a very quick growing space filler! Do not think that fennel needs to be babysat for long! Really the first few months are the real tentative moments but after that it will take care of itself until the end of the growing season.

Growing Fennel By Division

You will get some hit and miss results with this process. If you were to use division for oregano or sage it is nice and easy and the resulting plants will bush out quite quickly. This just doesn’t seem to be the case with fennel and you may regret it. Instead we grow by seed, or by purchasing plug plants from nurseries.

Timing is imperative with division and as fennel gives the best results from the second year onwards, you may need to wait until year three for this.

Don’t forget fennel will self seed and become a bit of a local bully. So division can seem a little surplus to requirements as well as a bit lack lustre.

How and What to Harvest

The herb fennel is incredibly versatile and you can harvest the leaves from a few months after sowing the seeds. This is perfect for salads and herbal teas that you want a more subtle flavor in. You may want to try a cold version of the tea using peppermint leaves and fennel leaves. This is very refreshing and there is nothing to stop you making it up into a cocktail with your alcohol of preference!

The flowers do make for a lovely arrangement and can be a real eye catcher in any home. However we like to leave the flowers in the garden for the bees to enjoy, the butterflies will also flock to it.

Once the flowers have bloomed and the blossom is starting to fade you will see what we commonly mistake as seeds growing. In fact that are the fruits of the plant. However we are going to collect them as seeds.

Cut the stem with around 12 inches of stalk plus the flower head. Tie them in bunches of around 10 stems. Hang them upside down with a paper bag over the heads of the flowers. As they dry the seeds will fall into the paper bag and give you a good supply.

Store the seeds in an airtight container. Use them in herbal teas. Use two teaspoons to crush the seeds and then pop them in to the infuser of the teapot.

Overwintering The Herb Fennel

This is where the herb differs from the vegetable. With the vegetable fennel you will find it a lovely annual. With the herb fennel, you can eat all parts of the plant, however leaving it in the ground, or pot over winter is perfectly fine.

Cut it back after you have harvested the seeds. Mulch around it and make sure to remove excess dead leaves from the base of the plant.

You may need to prune back further at the start of the second year as this will encourage a bushier plant. Be aware of the self seeding properties of fennel and even with the most diligent of pruning and removing of dead heads from flowers, it is still likely to have occurred.

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What Next?

Hopefully you will have seen that the herb fennel can be very versatile and work well in many different settings including in pots. We have used it as an ornamental perennial to fill spaces towards the back of our garden and hope to have encouraged you to give it a go as well!

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