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Growing Bulb Fennel Indoors

Bulb fennel is easy to grow indoors for tender little plants you can use in salads and sandwiches. Here are my best tips on how to grow it at home!

Bulb fennel to harvest

A small plate of beautiful bulb fennel for my sandwiches, voilà! Photo: Ida Sjöö.


For those of you who want an unusual but easy-to-grow vegetable you can harvest indoors, I recommend bulb fennel! It's the perfect vegetable to kick off the season with if you have a grow light at home for your little seedlings. Bulb fennel doesn't take up much space to grow indoors and provides plenty of taste that is well worth the minimal effort growing it.


Read more: Homemade pickled fennel


So, what is bulb fennel? Well, it's a delicious vegetable that we usually grow outdoors in the summer season. The plant develops a big bulb with a peculiar appearance and a taste of mild licorice. The foliage looks a little bit like dill. Generally, bulb fennel is considered a bit tricky to grow. We sometimes get great results that look just like the ones we get from the store. But just as often, we have issues getting any results at all. I actually think that this is what makes growing bulb fennel fun! The plants want just the right amount of everything and unfortunately, don't want to be sown in cold soil. If conditions were to change suddenly, the plants may respond by not forming the bulb at all, opting to bloom instead. Not good!


Beautiful bulb fennel

I like to grow fennel indoors during winter to have a unique vegetable for my tasty sandwiches. Here's fennel for crispbread with smoked herring pâté. Yum! Photo: Ida Sjöö.


Grow bulb fennel indoors

The bulb fennel we grow indoors won't be as large as the ones we have outside. But, we can absolutely grow tiny delicacies perfect for sandwiches, salads, and decoration inside. Just like with many other plants, the smaller ones are often the best-tasting.  A few weeks after sowing, a plate of fennel provides a luxurious harvest of greens that you can't find in your grocery store. The entire plant is edible, so don't throw the leaves away.


How to do it: 

  • Fill a deep dish or a small pot with potting soil.
  • Water.
  • Sprinkle the seeds on the soil, not too close together though.
  • Cover the seeds with soil
  • Optionally, place a piece of plastic over the soil to retain moisture while the seeds germinate
  • Store your sowing in room temperature.
  • Once germinated, let the fennel continue to grow under grow lights that are on for 12-16 hours a day.


It doesn't have to be harder than that. Since we don't plan on growing very large bulb fennel indoors, we don't need to think about anything in particular other than getting the seeds into the soil. The germination rate is often good, and the plants grow relatively quickly too!


Read more: How to pick a grow light


Sara harvests bulb fennel

I cut the fennel just above the soil. Photo: Ida Sjöö.

Fänkål att odla inomhus

The lower part of the plant is crispy and tastes mildly of licorice. Photo: Ida Sjöö.


Harvesting indoors

All plants we cultivate indoors will at some point start to grow slower and show clear signs of being dissatisfied with their current condition. They need to be repotted into larger pots, we need to give them more soil, more nutrients, more moisture. It's completely natural. However, it's best to eat the bulb fennel before this happens so that we don't have to move the bulb fennel to a new pot.  Repotted plants take up much more space, and the great thing about growing indoors is after all the space efficiency.

Usually, bulb fennel doesn't need fertilizer in the time between sowing and harvest. Everything the plant needs is in the soil, provided the soil is of good quality of course. It takes about six weeks to grow and harvest this indoor fennel.

Harvest by cutting the plant just above the soil, right where the stem divides and forms the base of the small bulb.

You can keep your fennel in a moisturized bag in the refrigerator. If they need freshening up, a small part of the stem can be cut off before placing the plant in a mug of water.


Read more: 10 vegetables you can grow indoors


Fröpåse med fänkål

There are several different varieties of bulb fennel out there. It is sometimes also called sweet fennel. 'Finale' is a good variety that produces robust plants suitable for outdoor cultivation too. Photo: Ida Sjöö.


Growing sandwich vegetables and little delicacies indoors in winter is really fun. And tasty too! Photo: Ida Sjöö.


You can eat your bulb fennel just as it is, including the stem and the leaves. It's really tasty on sandwiches and pairs wonderfully with meat toppings due to its mild licorice flavor. It can also be chopped and used in dressings and salads. If you get any leftovers, you can freeze them and use in vegetable salts, fish soups, and spice blends.


More: Follow me on YouTube


Bulb fennel that we grow outside in the garden is sown much later in spring. These plants shouldn't grow in chilly soil, as there's a high risk they won't form the large, nice bulb that we are after. That's why we wait until April-May to sow it outdoors.

Good luck with your bulb fennel!
/Sara Bäckmo


02. February 2024