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When to Plant Celeriac in Jefferson County, OR

Celeriac is a celery relative grown for its knobby, flavorful root rather than its stalks. It has a rich celery flavor and is excellent roasted, mashed, or in soups.

Jefferson County, Oregon is in USDA Zone 6a. The average last spring frost is June 9 and the first fall frost is September 19, giving you a growing season of approximately 102 days.

At an elevation of 21 feet, Jefferson County receives approximately 36.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79ยฐF, so choose short-season varieties of Celeriac to ensure they mature before fall.

Jefferson County, OR (Zone 6a) Short season
102 days
Last Spring Frost June 9
102 growing days
First Fall Frost September 19

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Sep 12 – Oct 17
Recommended (50%) ✗ May not fit
Start indoors: May 5 Transplant: Jun 9 🍅 Harvest: Sep 22 – Oct 27
Safe Start (90%) ✗ May not fit
Start indoors: May 18 Transplant: Jun 22 🍅 Harvest: Oct 5 – Nov 9

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
1.5″/week
Rainfall provides
1.5″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 12 gal / 100 sq ft
Celeriac needs ~1,018 GDD — county provides 943 GDD Tight fit

Celeriac Planting Timeline โ€” Jefferson County, OR

Celeriac Planting Calendar

Activity When Date Range
Start Indoors May 5 May 5 โ€“ May 19
Transplant Outdoors June 9 Jun 9 โ€“ Jun 23
Direct Sow May 26 May 26 โ€“ Jun 16
Fall Sowing July 11 Jul 11 โ€“ Jul 25
Harvest September 22 Sep 22 โ€“ Oct 27

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

100โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

102 days

Growing Tips for Jefferson County

Start seeds indoors 10-12 weeks before last frost. Remove side roots as they develop to encourage a single large bulb. Harvest after a light frost for best flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Level Up Your Garden

Frequently Asked Questions

When should I plant Celeriac in Jefferson County, OR?

Jefferson County is in Zone 6a with an average last frost of June 9. Plan your Celeriac planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jefferson County, OR?

Jefferson County, Oregon is in USDA Hardiness Zone 6a. The average last spring frost is June 9 and first fall frost is September 19.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jefferson County gardeners in Zone 6a 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 Jefferson County, OR. Local conditions may vary. Last updated: April 2026.