🌿 When to Plant Fennel
Direct sow or transplant; don't plant near dill (cross-pollinates)
📅 Planting Calendar by USDA Zone
Fennel is a cool-season crop — plant it around your last spring frost, and you can often start it earlier indoors or sow again for a fall harvest. Find the exact start-indoors, transplant, and direct-sow dates for your USDA zone in the table below.
Select your zone to highlight your dates. All dates are calculated from each zone's average frost dates — see how we calculate them.
| Zone | Last Frost | Start Indoors | Transplant | Direct Sow |
|---|---|---|---|---|
| Zone 2A | May 30 | May 2 | May 30 | May 30 |
| Zone 3B | May 15 | Apr 17 | May 15 | May 15 |
| Zone 4A | May 8 | Apr 10 | May 8 | May 8 |
| Zone 4B | May 1 | Apr 3 | May 1 | May 1 |
| Zone 5A | Apr 25 | Mar 28 | Apr 25 | Apr 25 |
| Zone 5B | Apr 18 | Mar 21 | Apr 18 | Apr 18 |
| Zone 6A | Apr 21 | Mar 24 | Apr 21 | Apr 21 |
| Zone 6B | Apr 10 | Mar 13 | Apr 10 | Apr 10 |
| Zone 7A | Apr 5 | Mar 8 | Apr 5 | Apr 5 |
| Zone 7B | Mar 28 | Feb 28 | Mar 28 | Mar 28 |
| Zone 8A | Mar 20 | Feb 20 | Mar 20 | Mar 20 |
| Zone 8B | Mar 12 | Feb 12 | Mar 12 | Mar 12 |
| Zone 9A | Feb 28 | Jan 31 | Feb 28 | Feb 28 |
| Zone 9B | Feb 15 | Jan 18 | Feb 15 | Feb 15 |
| Zone 10A | Feb 1 | Jan 4 | Feb 1 | Feb 1 |
| Zone 10B | Jan 15 | Dec 18 | Jan 15 | Jan 15 |
| Zone 11A | Jan 1 | Dec 4 | Jan 1 | Jan 1 |
Fennel is a beautiful, aromatic herb with a mild licorice flavor. Both bulb and herb types are worth growing.
Top Growing Tips
- Direct sow — fennel doesn’t transplant well
- Bulb fennel needs cool weather to form; herb fennel is more heat-tolerant
- Keep consistently moist for best bulb development
- Self-seeds prolifically if allowed to flower
- Attracts swallowtail butterflies — their caterpillars love it
Companion Planting
Good companions: dill (same family, attracts same beneficials)
Avoid planting near: most vegetables — fennel is somewhat allelopathic (inhibits nearby plants). Grow separately.
Harvest Timeline
Bulb: 65-90 days from seed; herb leaves anytime
Growing fennel in your region?
These dates come from your zone's frost windows. For the full month-by-month plan — succession sowing, variety picks, and timing tuned to your climate, not just your zone — our regional vegetable-gardening guides cover your area start to finish.
Find your regional growing guide