How to Grow Fennel

Start Fennel seeds indoors 4 weeks before your last frost date, then transplant outdoors -2 weeks after the last frost. Use the search on this page to find exact dates for your ZIP code or city.

Fennel typically matures in about 80 days from planting. Exact timing varies by variety, soil conditions, and local climate.

Fennel should be started indoors 4 weeks before the last frost date. This gives seedlings time to establish before being transplanted outside after frost danger has passed.

Fennel requires full sun to thrive.

Fennel has regular water needs. Consistent moisture is important especially during germination and early growth.

Yes — seed saving difficulty for Fennel is rated easy. Harvest umbels when seeds turn gray-green to brown — just before they drop. Cut seed heads into a bag, dry 1–2 weeks, thresh to separate seeds.

Properly dried and stored Fennel seeds remain viable for up to 4 years. Store in a cool, dark, dry location in an airtight container with a silica gel packet for best results.

Yes — Fennel is open-pollinated, meaning seeds saved from your harvest will grow plants true to the parent variety. This makes it an excellent candidate for building a self-sustaining garden.