There are two types of fennel:
- Florence fennel: grown primarily for the bulb-like base which is eaten as a vegetable. Leaves and seeds can also be harvested.
- Common and bronze fennel: grown for the seeds, but not recommended due to invasiveness.
When to plant
- Transplant or direct seed February–April (maybe May), September–October (maybe August).
- If growing from seed for transplants, allow 4 weeks to be ready.
- Harvest the bulb-like base when it is large and plump, 4–6" across, typically 60-90 days after transplanting. Cut just above the soil line.
- Pollen can be collected from flower blooms by shaking flower heads into a plastic bag.
- Pick leaves at any time during the growing season. Do not remove more than 1/3 of the foliage.
- Harvest seeds when flower heads turns brown. Cut the seedheads and place in a paper bag in a cool, ventilated, location. The seeds will fall off when dry and can then be collected.
- Fennel is perennial, but is grown as an annual for harvesting as bulbs.
- Fennel bulbs grow best in cool weather.
- Space 8–12 inches apart.
- Fennel will self-sow easily and can become weedy if not controlled. Common and bronze fennels are invasive pests in California.
- Fennel is a host plant for swallowtail butterflies.
- Fennel in the Garden, Utah State Extension
Recommended Varieties for Santa Clara County*
|Fennel Di Parma, OP||Superior bulbing fennel, large and uniform, with great flavor. Flowers attract beneficial insects, and swallowtail butterflies will lay eggs on the feathery greens. 24–36" tall. Plant 10–12" apart.|
* Many other varieties may also do well here in Santa Clara County. This list is based on UC Master Gardener trials, taste tests, and feedback from local growers.