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When to Plant Turnip in Benton County, OR

Turnips are a fast-growing cool-season root vegetable with edible roots and greens. Baby turnips are sweet and tender while mature ones are more pungent.

Benton County, Oregon is in USDA Zone 8a. The average last spring frost is April 14 and the first fall frost is October 30, giving you a growing season of approximately 199 days.

At an elevation of 97 feet, Benton County receives approximately 53.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Turnip during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Turnip root diseases.

Benton County, OR (Zone 8a) Moderate season
199 days
Last Spring Frost April 14
199 growing days
First Fall Frost October 30

Benton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (134 days to spare)
Transplant: Mar 27 🍅 Harvest: May 8 – Jun 12
Recommended (50%) ✓ Fits season (122 days to spare)
Transplant: Apr 14 🍅 Harvest: May 26 – Jun 30
Safe Start (90%) ✓ Fits season (129 days to spare)
Transplant: May 7 🍅 Harvest: Jun 18 – Jul 23

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Turnip needs ~688 GDD — county provides 2,736 GDD Excellent fit

Turnip Planting Timeline โ€” Benton County, OR

Turnip Planting Calendar

Activity When Date Range
Direct Sow March 31 Mar 31 โ€“ Apr 21
Fall Sowing August 21 Aug 21 โ€“ Sep 4
Harvest May 12 May 12 โ€“ Jun 16

Plant 0.5" deep ยท 4" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Direct Sow
April Direct Sow
May Harvest
June Harvest
July โ€”
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

40โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8a

Growing Season

199 days

Growing Tips for Benton County

Direct sow in early spring or late summer. Harvest when roots are 2-3 inches in diameter for best flavor. Both the roots and the greens are nutritious and edible.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Turnip in Benton County, OR?

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

What planting zone is Benton County, OR?

Benton County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is April 14 and first fall frost is October 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Benton 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 Benton County, OR. Local conditions may vary. Last updated: April 2026.