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When to Plant Fennel (herb) in Jackson County, OR

Herb fennel is grown for its aromatic leaves, stalks, and seeds rather than a bulb. It has a strong anise flavor and its flowers attract beneficial insects.

Jackson County, Oregon is in USDA Zone 8a. The average last spring frost is May 7 and the first fall frost is October 10, giving you a growing season of approximately 156 days.

At an elevation of 422 feet, Jackson County receives approximately 46 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Fennel (herb) during the growing season.

Jackson County, OR (Zone 8a) Moderate season
156 days
Last Spring Frost May 7
156 growing days
First Fall Frost October 10

Jackson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Mar 22 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 30
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Apr 2 Transplant: Apr 30 🍅 Harvest: Jul 2 – Sep 10
Safe Start (90%) ✓ Fits season (34 days to spare)
Start indoors: Apr 28 Transplant: May 26 🍅 Harvest: Jul 28 – Oct 6

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 85 gal / 100 sq ft
Fennel (herb) needs ~1,200 GDD — county provides 2,496 GDD Excellent fit

Fennel (herb) Planting Timeline โ€” Jackson County, OR

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 โ€“ Apr 16
Transplant Outdoors April 30 Apr 30 โ€“ May 14
Direct Sow April 23 Apr 23 โ€“ May 14
Fall Sowing August 1 Aug 1 โ€“ Aug 15
Harvest July 2 Jul 2 โ€“ Sep 10

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Fall Sowing Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 8a

Growing Season

156 days

Growing Tips for Jackson County

Direct sow in spring or fall. Unlike Florence fennel, herb fennel does not form a bulb. Harvest fronds as needed and seeds when they turn brown. Self-sows readily.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Green Beans

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Frequently Asked Questions

When should I plant Fennel (herb) in Jackson County, OR?

Jackson County is in Zone 8a with an average last frost of May 7. Plan your Fennel (herb) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jackson County, OR?

Jackson County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is May 7 and first fall frost is October 10.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jackson County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Jackson County, OR. Local conditions may vary. Last updated: April 2026.