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When to Plant Carrots in Columbia County, OR

Carrots are a popular root vegetable available in orange, purple, white, and yellow varieties. They are rich in beta-carotene and have a sweet, earthy flavor.

Columbia County, Oregon is in USDA Zone 8a. The average last spring frost is April 14 and the first fall frost is October 29, giving you a growing season of approximately 198 days.

At an elevation of 396 feet, Columbia County receives approximately 46.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Carrots during the growing season.

Columbia County, OR (Zone 8a) Moderate season
198 days
Last Spring Frost April 14
198 growing days
First Fall Frost October 29

Columbia County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (99 days to spare)
Transplant: Apr 7 🍅 Harvest: Jun 9 – Jul 14
Recommended (50%) ✓ Fits season (100 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 21
Safe Start (90%) ✓ Fits season (96 days to spare)
Transplant: May 10 🍅 Harvest: Jul 12 – Aug 16

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
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 20 gal / 100 sq ft
Carrots needs ~962 GDD — county provides 2,722 GDD Excellent fit

Carrots Planting Timeline โ€” Columbia County, OR

Carrots Planting Calendar

Activity When Date Range
Direct Sow March 31 Mar 31 โ€“ Apr 21
Fall Sowing August 20 Aug 20 โ€“ Sep 3
Harvest June 2 Jun 2 โ€“ Jul 7

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“80 days

Soil pH

6 โ€“ 6.8

USDA Zone

Zone 8a

Growing Season

198 days

Growing Tips for Columbia County

Sow seeds directly in loose, stone-free soil for straight roots. Keep soil moist until germination which can take 2-3 weeks. Thin seedlings to 2 inches apart.

Companion Planting

Good Companions

Avoid Planting Near

  • Dill
  • Parsnip

Level Up Your Garden

๐ŸŒพ Save Your Own Carrots Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Replant roots for 2nd year flowers. Harvest umbels when brown.
Storage Store airtight; viable 3 years at 35ยฐF, under 50% humidity.

Isolate 1/2 mile from Queen Anne's Lace (wild carrot). Biennial โ€” requires two seasons.

Frequently Asked Questions

When should I plant Carrots in Columbia County, OR?

Columbia County is in Zone 8a with an average last frost of April 14. Plan your Carrots planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Columbia County, OR?

Columbia County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is April 14 and first fall frost is October 29.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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