When to Plant Chinese Cabbage in Multnomah County, OR
Your May gardening checklist
Here's what deserves your attention in Multnomah County, Oregon this month. Everything below is tailored to Zone 9a and timed around your local frost dates.
-
Time to start chinese cabbage inside
These need a head start before your last frost (April 14). Sow into cells now so you're ready to transplant in a few weeks.
To set up a strong June, finish these tasks
- First harvests: chinese cabbage
Chinese cabbage (Napa cabbage) forms elongated, barrel-shaped heads with tender, mild-flavored leaves. It is a staple in Asian cooking, particularly for kimchi.
Multnomah County, Oregon is in USDA Zone 9a. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.
At an elevation of 357 feet, Multnomah County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Chinese Cabbage to ensure they mature before fall.
Multnomah County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.3
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 Multnomah County
How your county's soil matches Chinese Cabbage's growing requirements.
Soil pH
Your soil pH (5.8–6.3) overlaps with Chinese Cabbage's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Multnomah County is excellent for Chinese Cabbage — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Chinese Cabbage is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.
Organic Matter
Organic matter is excellent (4.5%) — Chinese Cabbage will thrive.
How to Plant Chinese Cabbage
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Chinese Cabbage
Sow every 5.7 weeks. Last sowing by Aug 18 to harvest before frost.
For a dedicated fall crop, sow by Sep 01.
Plant Water Budget
Monthly Watering Guide for Chinese Cabbage
Chinese Cabbage needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Chinese Cabbage Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.8" | 0" | ❄️ Dormant |
| Feb | — | 4.1" | 0" | ❄️ Dormant |
| Mar | — | 3.5" | 0" | ❄️ Dormant |
| Apr | 6.5" | 2.3" | 4.2" | 🚿 Regular watering |
| May | 6.5" | 2.3" | 4.2" | 🚿 Regular watering |
| Jun | 6.5" | 1.3" | 5.2" | 🚿 Regular watering |
| Jul | 6.5" | 0.6" | 5.9" | 🚿 Regular watering |
| Aug | 6.5" | 0.7" | 5.8" | 🚿 Regular watering |
| Sep | 6.5" | 1.6" | 4.9" | 🚿 Regular watering |
| Oct | 6.5" | 2.9" | 3.6" | 🚿 Regular watering |
| Nov | — | 6" | 0" | ❄️ Dormant |
| Dec | — | 4.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Multnomah County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Chinese 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.
Chinese Cabbage Planting Timeline — Multnomah County, OR
Chinese Cabbage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 17 | Mar 17 – Mar 31 |
| Transplant Outdoors | April 14 | Apr 14 – Apr 28 |
| Direct Sow | March 24 | Mar 24 – Apr 14 |
| Harvest | June 9 | Jun 9 – Jul 7 |
| Fall Sowing | September 1 | Sep 1 – Sep 15 |
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 | — |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
196 days in Multnomah County
Growing Tips for Chinese Cabbage in Multnomah County
Direct sow Chinese Cabbage outdoors after April 14 in Multnomah County when soil has warmed and frost danger has passed.
Common pests for Chinese Cabbage in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Best grown as a fall crop to avoid bolting. Start seeds indoors or direct sow in late summer. Keep soil consistently moist and provide shade in warm weather.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Chinese Cabbage in Other Locations
Frequently Asked Questions
When should I plant Chinese Cabbage in Multnomah County, OR?
Multnomah County is in Zone 9a with an average last frost of April 14. Plan your Chinese Cabbage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Multnomah County, OR?
Multnomah County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 14 and first fall frost is October 27.
Your Multnomah County Garden Planner — Free
A 24-page printable planner built for Multnomah County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.