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How to Take Care of a Fennel Plant

By Joshua Duvauchelle ; Updated September 21, 2017
Grow colorful fennel in your backyard.
A field of wild fennel grows in the hot sun image by david hutchinson from Fotolia.com

Fennel (Foeniculum vulgare) hails from the Mediterranean, but is now grown throughout North American herb gardens. Both its bulb and fibrous stalk are used in various entree recipes. Instead of buying fennel in a grocery store, grow your own fresh fennel. Cooks often find such freshly harvested fennel superior in flavor to the older fennel sold in stores. Provide your fennel plant with the care it needs to grow into a lush and mature herb.

Choose a gardening site. Fennel needs full sun for optimal growth and thrives best in well-drained soil.

Prepare the gardening area. Break up the soil into fine clumps with a spade. Fennel, like most herb species, does best in poor- to low-fertility soil. Though it doesn't need fertilization, it will respond favorably to 3 to 4 inches of aged compost mixed into the top 6 inches of dirt.

Plant the fennel seeds. Sow each seed 1/4 inch below the soil surface and space the seeds apart by a foot. If you're growing more than one row of fennel, space the rows apart by 36 inches, according to West Virginia University.

Water the fennel seeds. Apply water twice daily to keep the soil surface consistently moist. The seeds will typically germinate within two weeks.

Reduce watering to once every four to seven days as soon as the fennel seedlings are 1 to 2 inches tall. When watering, use enough water to moisten the soil to a depth of 6 inches.

Stake the fennel plants once they're 1 1/2 feet tall, according to West Virginia University. This helps keep the plant from falling over, critically important if your gardening area is windy. Pound a 36-inch-tall stake 12 inches into the ground approximately a foot from the fennel plant. Use garden twine and loosely tie the twine between the fennel plant's main stalk and the stake.

Watch for slugs and snails, which the University of California says are particularly drawn to fennel. Manual removal by plucking the snails and slugs off of the ground can control small populations. Large snail and slug infestations can be controlled with a chemical poison product, available at most garden stores.

Harvest the fennel by uprooting it once its bulb measures approximately 3 inches in diameter, according to the University of California.


Things You Will Need

  • Spade
  • Aged compost
  • Fennel seeds
  • Water
  • Wood stake
  • Garden twine


  • After seeding, it typically takes 100 to 120 days for fennel to be ready for harvest, according to Purdue University.

About the Author


Joshua Duvauchelle is a certified personal trainer and health journalist, relationships expert and gardening specialist. His articles and advice have appeared in dozens of magazines, including exercise workouts in Shape, relationship guides for Alive and lifestyle tips for Lifehacker. In his spare time, he enjoys yoga and urban patio gardening.