When to Plant Cabbage in Whatcom County, WA
Cabbage is a versatile cool-season crop that forms dense, leafy heads in green, red, or savoy varieties. It is a staple for coleslaw, sauerkraut, and many global cuisines.
Whatcom County, Washington is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.
At an elevation of 386 feet, Whatcom County receives approximately 49 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Cabbage during the growing season.
Whatcom County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
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 Whatcom County
How your county's soil matches Cabbage's growing requirements.
Soil pH
Your soil pH (5.2–6.4) is more acidic than Cabbage prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Whatcom County is excellent for Cabbage — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Cabbage will thrive.
How to Plant Cabbage
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Cabbage
Sow every 6.9 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 Cabbage
Cabbage needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.
| Month | Cabbage Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6.1" | 0" | ❄️ Dormant |
| Feb | — | 6.2" | 0" | ❄️ Dormant |
| Mar | — | 4.3" | 0" | ❄️ Dormant |
| Apr | 3.9" | 3.8" | 0.1" | 💧 Light watering |
| May | 3.9" | 3.1" | 0.8" | 💧 Light watering |
| Jun | 3.9" | 2.1" | 1.8" | 💧 Light watering |
| Jul | 3.9" | 0.7" | 3.2" | 🚿 Regular watering |
| Aug | 3.9" | 0.9" | 3" | 🚿 Regular watering |
| Sep | 3.9" | 2" | 1.9" | 💧 Light watering |
| Oct | 3.9" | 4.5" | 0" | ✅ Rainfall sufficient |
| Nov | — | 7.1" | 0" | ❄️ Dormant |
| Dec | — | 8.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Whatcom County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Cabbage 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.
Cabbage Planting Timeline — Whatcom County, WA
Cabbage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 2 | Mar 2 – Mar 16 |
| Transplant Outdoors | April 6 | Apr 6 – Apr 20 |
| Direct Sow | March 23 | Mar 23 – Apr 13 |
| Harvest | June 8 | Jun 8 – Aug 3 |
| 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 | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.9"/week · Natural rainfall sufficient
📅 Days to Maturity
60–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 7b
📆 Growing Season
206 days in Whatcom County
Growing Tips for Cabbage in Whatcom County
Direct sow Cabbage outdoors after April 06 in Whatcom County when soil has warmed and frost danger has passed.
Common pests for Cabbage in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 4-6 weeks before last frost. Space plants 18-24 inches apart. Keep soil evenly moist to prevent heads from splitting.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Cabbage in Other Locations
Frequently Asked Questions
When should I plant Cabbage in Whatcom County, WA?
Whatcom County is in Zone 7b with an average last frost of April 6. Plan your Cabbage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Whatcom County, WA?
Whatcom County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 29.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Whatcom County gardeners in Zone 7b 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.