Bulb Fennel: Learn About When And How To Harvest Fennel Bulbs

fennel-bulbs
Image by Stacy Spensley

By Jackie Rhoades

How and when do I harvest my bulb fennel? These are common questions and learning how to harvest fennel bulbs isn’t difficult at all. When to harvest fennel bulbs involves a little more, but before we talk about the how and the when, let’s make sure we’re talking about the right fennel.

Fennel is an herb that grows freely in gardens throughout the USDA hardiness zones 5-10. The seeds and leaves can be used in a variety of recipes, including the flavoring for Italian sausage, and the leaf stalks make a different and wonderful vegetable dish.

There are several species available for this use, including Foeniculum vulgare (common fennel), the wild fennel that grows along the roadsides in many parts of the United States, but if you want to talk about harvesting fennel bulbs for your table, you must plant Florence fennel, a variety of Foeniculum vulgare called Azoricum. In Italy, where this variety has been cultivated for centuries, it is called finocchio. This is the only variety to plant if your goal is harvesting fennel bulbs.

When to Harvest Fennel Bulbs

When do I harvest my bulb fennel? Fennel bulbs take about twelve to fourteen weeks from seed to harvest and depend on cool weather for bulb development. If the weather becomes unseasonably warm, all fennel, including finocchio, will bolt. This means it will produce flowers too soon and the bulb won’t form, but when conditions are right, when to harvest fennel bulbs depends solely on their size.

As the bulb grows, measure it with a ruler. The bulb should measure at least 5 cm in length but no more than 7 cm (2-3 inches), about the size of a tennis ball. Harvesting fennel bulbs larger than this will be disappointing. They tend to get stringy and tough with age.

Now that you know when to harvest fennel, let’s talk about how to harvest fennel bulbs.

How to Harvest Fennel Bulbs

Use a pair of garden shears or a sharp knife to cut off the plant’s stalks and leaves, leaving an inch or two at the top of the bulb. Don’t discard the greenery! Use them for another dinner as a salad addition or side dish.

Carefully clear the soil away from the base of the bulb. If your soil is loose, you can use your hands for this. If not, you a small garden trowel. Try not to nick the bulb. Now hold the bulb and using a sharp knife, slice the bulb away from the roots. Ta-da! You’ve just learned how to harvest fennel bulbs!

Clean your fennel bulbs with water and, if possible, use them right away while the flavor is most potent. If you can’t use it immediately, store it in an airtight plastic bag in the refrigerator for up to a week, but please remember your bulb will begin to lose flavor as soon as it is cut. Use it as quickly as possible.

So, when do I harvest my bulb fennel? Right when I need it. I plant my seeds a few at a time so my bulbs don’t all form at once. I slice them in salads and stir-fry or roast them or braise them and enhance their flavor with mild Italian cheese. They’re a different and enjoyable dinner time treat that can only be had during a limited time of year, and that makes them something special.

Harvesting fennel bulbs straight from your garden can be a treat for you, too.

This article was last updated on

Related Articles
Did you find this helpful?
Share it with your friends!
Additional Help & Information

Didn't find the answer to your question? Ask one of our friendly gardening experts.

Do you know anything about gardening? Help answer someone's gardening question.

Read more articles about Fennel Bulb.

Search for more information

Use the search box below to find more gardening information on Gardening Know How:

Newest Articles
  • orchid-pseudobulbs What Is A Pseudobulb In Orchids: Learn About The Function Of Pseudobulbs
  • jasmine-flower Non-Flowering Jasmine: When Jasmine Flowers Are Not Blooming
  • grapes Ripening Of Grapes: When To Harvest Grapes
  • bells-of-ireland Bells Of Ireland Care: Tips For Growing Bells Of Ireland Flowers
  • mamey-fruit What Is A Mamey Tree: Mamey Fruit Info And Cultivation