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When to Plant Rutabaga in Columbia County, WA

Columbia County, Washington Zone 7a May

Your May gardening checklist

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Columbia County, Washington.

Avg. last frost April 28
Avg. first frost October 11
Soil temp (4") 56°F
Watering High
Pest pressure Low
Daylight 14.8 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.

Columbia County, Washington is in USDA Zone 7a. The average last spring frost is April 28 and the first fall frost is October 11, giving you a growing season of approximately 166 days.

At an elevation of 3,157 feet, Columbia County receives approximately 21.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Rutabaga during the growing season.

Columbia County, WA (Zone 7a) Moderate season
166 days
Last Spring Frost April 28
166 growing days
First Fall Frost October 11
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Columbia County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Transplant: Apr 18 🍅 Harvest: Jul 11 – Aug 15
Recommended (50%) ✓ Fits season (47 days to spare)
Transplant: Apr 28 🍅 Harvest: Jul 21 – Aug 25
Safe Start (90%) ✓ Fits season (43 days to spare)
Transplant: May 18 🍅 Harvest: Aug 10 – Sep 14

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 Columbia County

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

Soil pH

Your soil pH (5.5–6.5) overlaps with Rutabaga's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — 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.

Succession Planting Rutabaga

2
successive plantings in your 166-day season

Sow every 9.1 weeks. Last sowing by Jul 03 to harvest before frost.

For a dedicated fall crop, sow by Aug 02.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 234 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 3" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 3" 1.7" 1.3" 💧 Light watering
May 3" 1.4" 1.6" 🚿 Regular watering
Jun 3" 0.9" 2.1" 🚿 Regular watering
Jul 3" 0.3" 2.7" 🚿 Regular watering
Aug 3" 0.3" 2.7" 🚿 Regular watering
Sep 3" 0.9" 2.1" 🚿 Regular watering
Oct 3" 1.9" 1.1" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Columbia 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 ~1,575 GDD — county provides 2,905 GDD Excellent fit

Rutabaga Planting Timeline — Columbia County, WA

Rutabaga Planting Calendar

Activity When Date Range
Direct Sow April 14 Apr 14 – May 5
Harvest July 7 Jul 7 – Aug 11
Fall Sowing August 2 Aug 2 – Aug 16

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7a

📆 Growing Season

166 days in Columbia County

Growing Tips for Rutabaga in Columbia County

Direct sow Rutabaga outdoors after April 28 in Columbia 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 Columbia County, WA?

Columbia County is in Zone 7a with an average last frost of April 28. Plan your Rutabaga planting based on this frost date — see the calendar above for exact timing.

What planting zone is Columbia County, WA?

Columbia County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 28 and first fall frost is October 11.

🌱

Your Columbia County Garden Planner — Free

A 24-page printable planner built for Columbia County (Zone 7a). 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 Columbia County, WA. 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.