When to plant fennel 🌿
Fennel takes 60–90 days to mature, spaced 8" apart at 0.25" deep. Start indoors and transplant for the longest harvest.
Planting dates by USDA zone
| Zone | Start indoors | Direct sow | Transplant | Harvest |
|---|---|---|---|---|
| Zone 3 | April 13 – April 27 | May 11 – June 8 | May 11 – May 25 | August 3 – August 24 |
| Zone 4 | April 3 – April 17 | May 1 – May 29 | May 1 – May 15 | July 24 – August 14 |
| Zone 5 | March 20 – April 3 | April 17 – May 15 | April 17 – May 1 | July 10 – July 31 |
| Zone 6 | March 4 – March 18 | April 1 – April 29 | April 1 – April 15 | June 24 – July 15 |
| Zone 7 | February 19 – March 4 | March 18 – April 15 | March 18 – April 1 | June 10 – July 1 |
| Zone 8 | February 2 – February 16 | March 1 – March 29 | March 1 – March 15 | May 24 – June 14 |
| Zone 9 | January 4 – January 18 | February 1 – February 29 | February 1 – February 15 | April 25 – May 16 |
| Zone 10 | December 19 – January 2 | January 16 – February 13 | January 16 – January 30 | April 9 – April 30 |
Dates are averages — adjust ±1–2 weeks for your microclimate. Need your exact dates? Enter your zip code below.
Get your personalized fennel planting dates
Care tips
- Hill soil around bulbs to keep them sweet.
- Allelopathic — keep away from most veggies.
- Bolts in heat; best as spring/fall crop.
Good companions
Plant alone — keep away from beans, tomato, dill.
Read more: Companion planting chart for vegetables
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Frequently asked questions
When should I start fennel seeds indoors in zone 5?▾
In USDA zone 5, start fennel seeds indoors between March 20 and April 3 — that's 4–6 weeks before the average last frost (May 1).
When should I start fennel seeds indoors in zone 6?▾
In USDA zone 6, start fennel seeds indoors between March 4 and March 18 — that's 4–6 weeks before the average last frost (April 15).
When should I start fennel seeds indoors in zone 7?▾
In USDA zone 7, start fennel seeds indoors between February 19 and March 4 — that's 4–6 weeks before the average last frost (April 1).
When should I start fennel seeds indoors in zone 8?▾
In USDA zone 8, start fennel seeds indoors between February 2 and February 16 — that's 4–6 weeks before the average last frost (March 15).
When can I transplant fennel seedlings outdoors?▾
Transplant fennel seedlings about -2–0 weeks after your average last spring frost. In zone 6 that's around April 1–April 15.
How long does fennel take to grow?▾
Fennel typically takes 60–90 days to mature, with harvest beginning roughly 10–13 weeks after the last spring frost.