Fennel care guide

Foeniculum vulgare

Also known as: Sweet fennel, Florence fennel

Pets and children

We haven't been able to confirm how this plant affects pets or small children. If any is eaten, consult a veterinarian or a doctor.

How often to water Fennel

Spring–Summer (Mar–Sep)
Every 2 days
Water thoroughly once the topsoil is dry, as a guide; a big plant drinks a lot, so check in the morning in midsummer.
Autumn (Oct–Nov)
Every 4 days
Cooler weather slows drying, so water a day or two after the soil dries, as a guide.
Winter (Dec–Feb)
Every 7 days
With the top died back and resting, a light watering a few days after the soil dries is the guide.

Light and placement for Fennel

Generally wants full sun, with a sunny outdoor spot as the guide; it reaches about 1 to 2 m, so pick a sheltered spot or have a stake ready.

Overwintering Fennel

Overwintering guide: −10°C (14°F) or above

A hardy perennial that generally stays outdoors over winter as a guide: the top dies back and new shoots rise from the base in spring, with sparing water in between.

Fertilizing and repotting Fennel

Fertilizer

Needs little: a bit of slow-release fertilizer or diluted liquid feed about twice a month in spring and fall, as a guide, and none in midsummer or winter.

When to repot

Spring–Summer (Mar–Sep), Autumn (Oct–Nov)

Common problems with Fennel

  • Transplanting damages the taproot and the plant declines and dies.
  • Swallowtail caterpillars strip the foliage.
  • In a small pot it dries out constantly and the lower leaves yellow.
  • It grows tall and is knocked over by wind.

Tips for growing Fennel

  • Sow directly in a deep pot, or plant while small without disturbing the roots.
  • It crosses easily with dill planted nearby, so keep the two apart.
  • The flowers and seeds are fragrant too; dry the seeds for use as a spice.

These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.

Keep your plant log going

Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.

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