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When to Plant Rutabaga in Union County, OR

Union County, Oregon Zone 6b May

Union County, Oregon gardeners: here's your May plan

A quick May briefing for Union County, Oregon gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 12
Avg. first frost September 26
Soil temp (4") 53°F
Watering High
Pest pressure Low
Daylight 14.7 hrs

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Rutabagas are a cross between turnips and cabbage, producing large yellow-fleshed roots with a sweet, mild flavor. They are excellent mashed, roasted, or in stews.

Union County, Oregon is in USDA Zone 6b. The average last spring frost is May 12 and the first fall frost is September 26, giving you a growing season of approximately 137 days.

At an elevation of 2,751 feet, Union County receives approximately 23.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Rutabaga during the growing season.

Union County, OR (Zone 6b) Short season
137 days
Last Spring Frost May 12
137 growing days
First Fall Frost September 26

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Transplant: May 3 🍅 Harvest: Jul 26 – Aug 30
Recommended (50%) ✓ Fits season (18 days to spare)
Transplant: May 12 🍅 Harvest: Aug 4 – Sep 8
Safe Start (90%) ✓ Fits season (14 days to spare)
Transplant: Jun 8 🍅 Harvest: Aug 31 – Oct 5

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.

Soil Compatibility in Union County

How your county's soil matches Rutabaga's growing requirements.

Soil pH

Your soil pH (5.2–6.6) is more acidic than Rutabaga prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Union County is excellent for Rutabaga — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Rutabaga.

Organic Matter

Organic matter is excellent (5.6%) — Rutabaga will thrive.

How to Plant Rutabaga

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 231 gal / 100 sq ft

Monthly Watering Guide for Rutabaga

Rutabaga needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Rutabaga Needs Rainfall You Supplement Action
Jan 2.9" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 3" 1.5" 1.5" 🚿 Regular watering
Jun 3" 0.9" 2.1" 🚿 Regular watering
Jul 3" 0.4" 2.6" 🚿 Regular watering
Aug 3" 0.5" 2.5" 🚿 Regular watering
Sep 3" 1" 2" 🚿 Regular watering
Oct 2" 0" ❄️ Dormant
Nov 3.8" 0" ❄️ Dormant
Dec 4.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Union County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Rutabaga Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Rutabaga needs ~1,305 GDD — county provides 1,986 GDD Excellent fit

Rutabaga Planting Timeline — Union County, OR

Rutabaga Planting Calendar

Activity When Date Range
Direct Sow April 28 Apr 28 – May 19
Harvest July 21 Jul 21 – Aug 25
Fall Sowing July 18 Jul 18 – Aug 1

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

137 days in Union County

Growing Tips for Rutabaga in Union County

Direct sow Rutabaga outdoors after May 12 in Union County when soil has warmed and frost danger has passed.

Common pests for Rutabaga in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in early summer for fall harvest. Thin seedlings to 6-8 inches apart. Flavor improves significantly after a few light frosts.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rutabaga in Union County, OR?

Union County is in Zone 6b with an average last frost of May 12. Plan your Rutabaga planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, OR?

Union County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is May 12 and first fall frost is September 26.

🌱

Your Union County Garden Planner — Free

A 24-page printable planner built for Union County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Union County, OR. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.