When to Plant Rutabaga in Cowlitz County, WA
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.
Cowlitz County, Washington is in USDA Zone 8a. The average last spring frost is April 15 and the first fall frost is October 29, giving you a growing season of approximately 197 days.
At an elevation of 268 feet, Cowlitz County receives approximately 47.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Rutabaga during the growing season.
Cowlitz County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.5
Drainage
Well Drained
Plant Planting Risk Windows
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 Cowlitz County
How your county's soil matches Rutabaga's growing requirements.
Soil pH
Your soil pH (5.7–6.5) overlaps with Rutabaga's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Cowlitz County is excellent for Rutabaga — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.3%) — Rutabaga will thrive.
How to Plant Rutabaga
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Rutabaga
Sow every 9.1 weeks. Last sowing by Jul 21 to harvest before frost.
For a dedicated fall crop, sow by Aug 20.
Plant Water Budget
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 | — | 7.2" | 0" | ❄️ Dormant |
| Feb | — | 4.6" | 0" | ❄️ Dormant |
| Mar | — | 5.1" | 0" | ❄️ Dormant |
| Apr | 3" | 3.6" | 0" | ✅ Rainfall sufficient |
| May | 3" | 2.9" | 0.1" | 💧 Light watering |
| Jun | 3" | 2" | 1" | 💧 Light watering |
| Jul | 3" | 0.8" | 2.2" | 🚿 Regular watering |
| Aug | 3" | 0.9" | 2.1" | 🚿 Regular watering |
| Sep | 3" | 1.6" | 1.4" | 💧 Light watering |
| Oct | 3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 7.6" | 0" | ❄️ Dormant |
| Dec | — | 7.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Cowlitz 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 Planting Timeline — Cowlitz County, WA
Rutabaga Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 1 | Apr 1 – Apr 22 |
| Harvest | June 24 | Jun 24 – Jul 29 |
| Fall Sowing | August 20 | Aug 20 – Sep 3 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
80–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 8a
📆 Growing Season
197 days in Cowlitz County
Growing Tips for Rutabaga in Cowlitz County
Direct sow Rutabaga outdoors after April 15 in Cowlitz 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
Check more plant combinations with our Companion Planting Checker →
Rutabaga in Other Locations
Frequently Asked Questions
When should I plant Rutabaga in Cowlitz County, WA?
Cowlitz County is in Zone 8a with an average last frost of April 15. Plan your Rutabaga planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cowlitz County, WA?
Cowlitz County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 15 and first fall frost is October 29.
Plan Your Garden with Confidence
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