Planting Guide and Seed Saving Notes for Fennel

Fennel (Foeniculum vulgare)

Fennel is a beautifully majestic plant with delicate fern-like leaves that produce a crisp, sweet bulb above the soil. The fennel bulb has a distinctive anise flavor that makes this a favorite ingredient for many chefs. And don't worry if the spring planting bolts! The flowers will attract beneficial insects and then produce fresh fennel seeds that can be tossed into any dish.  

How to Grow Fennel from Seed

Bed Preparation

Fennel is a perennial that prefers rich, moist but well-drained soil. Choose a site with full sun. Drought tolerant once established.


Direct sow fennel seed outdoors in spring or fall. Optimal germination occurs when soil temps are 60-85 F. Seed can also be started indoors in spring 4 weeks before the last frost. Disturbing the roots can cause bolting, so choose containers that are large enough to avoid root bound plants.

Soaking seed for 4 days prior to planting aids in germination. Sow seeds 1/2" deep and 3-4" apart. Seeds will sprout in 5-17 days. Transplant seedlings outdoors once danger of frost has passed. Thin seedlings so that mature plants are 12" apart.


Harvest in late summer through fall by cutting through the tap root at the soil line.

How to Save Fennel Seeds

Fennel is a short-lived perennial that self-sows readily. Seeds mature in fall. Collect seeds when flowers have dried and turned brown. Store seeds in a cool dry place. Seeds will remain viable for 3-4 years.