Cool-Season Vegetable

When to Plant Fennel (Bulbing)

Mediterranean vegetable producing crisp, anise-flavored bulbs. Beautiful ferny foliage adds elegance to the garden.

Sun

Full sun (6+ hours)

Water

1 inch per week

Days to Harvest

65-90

Difficulty

intermediate

Spacing

12"

Frost Tolerance

moderate

The Short Answer

Fennel (Bulbing) are cold-tolerant and actually prefer cooler growing conditions. Enter your zip code on our homepage tool for exact dates.

How to Grow Fennel (Bulbing)

Bulbing fennel (Florence fennel) is one of the more challenging cool-season crops — it bolts easily when transplanted, when stressed, or when day length increases rapidly. Direct sow in mid-to-late summer for a fall harvest when declining day length reduces bolting. Hill soil around the developing bulb to blanch it white. The anise flavor mellows dramatically when roasted or grilled. Important garden note: fennel is allelopathic — it chemically inhibits the growth of most other vegetables. Plant it in an isolated spot, away from the main garden.

Direct Sowing

Fennel (Bulbing) can be direct sown 0 weeks after your last frost date. Plant seeds 0.25" deep, spaced 12" apart.

Fall Planting

Fennel (Bulbing) are planted in fall, 10 weeks before your average first frost date. Plant 0.25" deep, 12" apart.

Growing Tips

Plant fennel AWAY from other vegetables — it inhibits growth of most garden crops. Direct sow only — it bolts easily when transplanted. Hill soil around bulbs as they develop. Best as a fall crop when declining day length reduces bolting.

Companion Planting

Good companions:

Dill

Keep away from:

Tomatoes Peppers Beans Most Vegetables

Fennel (Bulbing) Planting Dates by State

Click your state for fennel (bulbing) planting dates specific to your location:

Note: Planting dates are based on average frost dates from NOAA Climate Normals (30-year averages). Actual conditions vary year to year. Always check your local forecast before planting frost-sensitive crops.

Last reviewed: March 29, 2026