Annual herb
Fennel plant profile
Foeniculum vulgare
An annual herb for full sun.
Last updated .
When to plant
When to plant Fennel
Start seeds indoors
6 weeks before your last spring frost to 4 weeks before your last spring frost
Direct sow
at your last spring frost
Growing conditions
- Sun
- Full sun
- Water
- 2 in / week
- Planting depth
- 0.25 in
- Soil pH
- 6.5 to 8
- Lifecycle
- Annual
- Spacing
- 8 to 12 in apart, rows 18 in
- Days to maturity
- 60 to 90 days (from sowing)
Common problems
Watch for these
Also watch for: stalk splitting.
Evidence trail
Evidence behind this profile
Original extension and institutional publications behind the planting, care, and safety facts on this page.
- How to Grow Fennel in Your Garden
Utah State University Extension. Supports indoor seed-starting timing (direct), direct-sowing timing (normalized), and days to maturity (direct). Checked 2026-06-13.
- Toxic and Non-Toxic Plants: Fennel (Foeniculum vulgare) entry
ASPCA Animal Poison Control Center. Supports pet-safety verdicts for dogs and cats. Checked 2026-07-18.