Fennel is easy to grow – even in the arid Southwest. Here are my tips for growing this cool season crop.  Note that fennel is a member of the carrot family, so a number of other carrot family herbs can be grow in this same way.  The list includes caraway, cilantro, cumin, dill, parsley, and some others I am blanking on at the moment.

Fennel is Entirely Edible

What I appreciate about fennel is that the entire fennel plant is useful. Leaves, roots, stems, flowers, and seed are all edible.    Leaves, roots, stems, and flowers can be eaten raw, steamed, or added to soups and stews.   Meanwhile, the seeds are used as a condiment (spice) in beef dishes, in breads, and in cakes, depending on nationality.  Fennel seeds are also considered medicinal in some traditions.

Good for Wildlife Too

Fennel looks fine in the garden, plus attracts winged wildlife.    Butterflies, birds, and the bees all visit the plants.    Bees and butterflies pollinate the blooms, while birds such as the lesser goldfinch, adore the oil rich seeds.

You may also see some caterpillars on your plants, enjoying the leaves. All members of this carrot family are host plants for various species of swallowtail butterflies. Indeed, social media becomes flooded worried posts asking “what’s eating my plant?!”  Unless you are literally starving to death, just let Nature be Nature, and let these butterfly babies eat and grow.  Because the larva pupate into such lovely butterflies, I always plant enough so there is plenty of fennel for me and enough for baby butterflies too.

Learn About Nature

If you are homeschooling, buy or make a butterfly house (an empty fish tank with a screen on top works).  Bring in your butterfly babies and observe the caterpillars as they eat, grow, form their chrysalis, and then emerge as adult butterflies. Simply recording your daily observations in pictures or words is how many young scientists (like Linneaus) started their careers.

Do some more in-depth science.  Make and test a hypothesis or two.  Will a caterpillar started on fennel switch to parsley from the store?  How about cilantro?  Will different caterpillars raised on different foods look different when they emerge as adults?

Grow Green

Growing fennel (and as many of your own herbs as you can) helps reduce your carbon footprint.    Besides, once you taste the awesome flavor to be had from fresh from the garden herbs, you will never willingly go back to store bought.

How to Grow Fennel

Which Fennel to Grow

For eating the swollen base or “bulb,” select “sweet fennel.”

Growing for seed – you merely need “fennel.”

For leaves only, select the decorative “bronze fennel.”

Local nurseries carry fennel seedlings, or you can start plants from seed.

When to Start

In Low, Middle, and Upper Desert (USDA Zones 10, 9, 8, and 7B) in the Southwest, start fennel in September or October as part of your winter vegetable garden.

In all locations – start seed at least 4 weeks before first frost, 6 to 8 weeks would be better. Once soil temperatures are below 72F. Since I am posting this in mid-October 2026 – readers in cooler locations should start fennel from seedlings from your local nursery. Do be very careful when transplanting them, they are a tad fussy about disturbed roots.

How to Plant

Sow seeds a quarter inch deep in rows around eighteen inches apart. When seedlings are two inches high, thin them to stand around a foot apart.

Or they also look nice planted as a clump in a flower bed. This is especially true for bronze fennel.

Planting & Care by the Five Greek Elements

Earth (Soil)

Like most herbs from the Old World brought to this New World, fennel grows best in a well drained, slightly acidic soil, rich in organic matter.    It is not a fan of our alkaline desert soil.

Fennel is also easy to grow in containers.    Use a pot one and a half feet deep.    Potting soil with some added sand makes a good growing media.

Air (Temperature & Wind)

Once fennel has about 5 to 8 leaves, it is “established,” and can take a light freeze. This means you may need to plant it in containers on or near your porch where you can drag the containers in next to the home in case of a hard freeze. Such a protected location helps them survive.

Choose a spot that is protected from high winds. Towards the end of the season the tall hollow stalks of fennel can easily be broken and blown over. If you were trying to get seed this would be a disaster.

Expert Gardeners Trick

Place a tomato cage around young fennel plants and allow them to grow inside the cage. 
In case of frost, you can easily cover the cage with a blanket. 
In case March roars in like a lion, you already have a cage in place to hold the stalk upright against strong winds.

Fire (Sunlight)

Fennel needs six or more hours of winter sun per day to do well.

Water

Keep the soil evenly moist but not waterlogged during “establishment.”    Once plants have 5 to 8 leaves they are considered “established” and now you can let fennel soil dry a little between waterings.    Some people believe this makes the flavor stronger.

Ether (Care or Fertilizer)

Fennel generally does not require fertilizer.  That is if you amended your soil at the start of the growing season – then the plants should do fine from seed to seedling, to plant, to setting seed.   One reason I avoid fertilizer is that fertilizing encourages fast growth – not a good idea if frosts are a possibility.  Another issue is that if you use too much nitrogen fertilizer, you won’t get flowers, and I do like fennel seeds for cooking and as to make a cordial. (How to make cordials on Savor the Southwest)

Harvest & Storage of Fennel

Harvest fresh leaves as you desire for use.    I munch on them as I work in the garden, toss them in salads or use in stir fry.

Harvest fennel bases once they reach softball size.

Harvest seed once the stalks have started to dry out and turn brownish. Simply cut the stalks and tip the entire mass of seed heads and stalks into a large paper bag.    Let this dry for several weeks before cleaning and storage.    Store all herbs (or seeds for growing) in airtight containers out of direct sunlight.

All in all, fennel is fairly fantastic. (Yep, I do like alliteration).

Butterfly Plant Book

Here is a short list of some of the more popular southwestern plants for butterfly gardens. For a more complete list, plus how to grow these plants see my book Butterfly Gardening in Southern Arizona, Revised Edition.

It says “southern Arizona” because I am nerdily precise, and when I first wrote it I had not done enough research on other parts of the Southwest.  I now know that the plants discussed in this handy guide  will grow in Southern Nevada, Eastern California, Across the deserts of Arizona, into Southern New Mexico, and through Big Bend into the Texas Hill Country.

Published by locally by Tierra del Sol Institute – whose mission statement is “Helping people live in harmony with their environment.”  All the profits from the sale of the book go to their Horticulture Therapy programs.

Note.  This slender volume was printed in Tucson at Arizona Litographers, the first ever printing press in America to be run entirely on green energy.  They have won awards for their efforts to reduce impact upon the earth, and thus fit well with the Tierra del Sol mission to help people live more lightly on this earth.

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