How to Grow Fennel: A Toronto Master Gardeners Guide

Fennel (Foeniculum vulgare). Fennel, like its close relative dill, is grown for its frond-like leaves, which are harvested and used fresh (especially in fish dishes) and for its seeds, which have many uses in the kitchen. All fennel varieties are attractive — in particular bronze-leaved fennel (Foeniculum vulgare ‘Purpureum’) — and lend themselves to being incorporated into a mixed bed.  Fennel flowers attract many beneficial insects.

Cultivation: Fennel is a tender perennial grown in Ontario as an annual. Since it does not transplant well, sow seeds directly in the ground once the soil warms up (15°C) or in the same pots where it is to be grown. Fennel thrives in full sun and soil rich with organic matter. Once established, it is drought tolerant. Fennel may reach one metre or more in height, so it should be placed with this in mind.

Leaves can be harvested as needed as soon as there is sufficient growth, and continue through to autumn. Seeds can be dried for winter use. Fennel self-seeds readily and can become an unwelcome weed unless the seed heads are removed.

Fennel is prone to aphid infestation and also attracts black swallowtail caterpillars, which may temporarily cause significant damage.

Florence Fennel (Foeniculum vulgare var. dulce) is grown for its swollen ‘bulb’ rather than its fronds and seeds and is eaten as a vegetable.

Disclaimer: Toronto Master Gardeners does not advise or recommend herbs for medicinal or health use. Any information in the recommended resources should be regarded as being for educational purposes only and should not be considered as a recommendation or an endorsement of any medical or health treatment.

 For more information:

(MDC) Missouri Department of Conservation:



West Coast Seeds

University of Illinois Extension, Growing Herbs – Fennel


Date prepared: December 2021

Prepared by the Toronto Master Gardeners, these Gardening Guides provide introductory information on a variety of gardening topics.  Toronto Master Gardeners are part of a large, international volunteer community committed to providing the public with horticultural information, education and inspiration.  Our goal is to help Toronto residents use safe, effective, proven and sustainable horticultural practices to create gardens, landscapes and communities that are both vibrant and healthy.

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Statement on Home Remedies: The Toronto Master Gardeners do not recommend home remedies, as these have not been proven effective through scientific investigation, and may even damage other living organisms in the soil or plants in your garden.  There are other garden friendly options you can use.

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