Fennel — Growing reference
| Scientific name | Foeniculum vulgare var. azoricum |
|---|---|
| Seed germination (days) | 7–14 |
| Soil temperature for germination (°C) | 15.6–23.9 |
| First harvest or flowering (days) | 65–90 |
| Measured from | Seed |
| Plant spacing (cm) | 15.2–30.5 |
| Mature height (cm) | 45.7–91.4 |
| Mature spread (cm) | 30.5–45.7 |
| USDA hardiness zones | 4–11 |
| Light | Full sun |
| Water | Moderate |
| Sowing method | Direct sow |
Growing directions
Direct sow seeds 1/4 inch deep in spring 4 weeks before last frost or in late summer for fall harvest, thinning to 6–12 inches apart; Florence fennel (finocchio) forms a crisp, anise-flavored bulb at the base of overlapping leaf sheaths and should be harvested when the bulb reaches 3–4 inches in diameter before it bolts in heat. Hill soil up around the bulb base 2–3 weeks before harvest to blanch it to a sweeter, more tender white. Succession-sow every 3 weeks for an extended harvest. Keep fennel away from tomatoes, peppers, and most garden vegetables as it produces allelochemicals that inhibit their growth — plant it at the garden edge or in its own dedicated bed.
Source and local conditions
Typical planning ranges from OpenPlantDB (CC0). Cultivar, climate, season and growing method can change these values. Confirm the seed label and local guidance before planting.
Source & verification
OpenPlantDB · CC0