When to Plant Celery in Multnomah County, OR
What to do in May
Your Multnomah County, Oregon garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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Indoor seed-starting week for celery
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.
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 Celery 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 Celery's growing requirements.
Soil pH
Your soil pH (5.8–6.3) overlaps with Celery's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Multnomah County is excellent for Celery — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Celery is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.
Organic Matter
Organic matter is excellent (4.5%) — Celery will thrive.
How to Plant Celery
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Celery
Sow every 9.1 weeks. Last sowing by Jun 29 to harvest before frost.
For a dedicated fall crop, sow by Sep 01.
Plant Water Budget
Monthly Watering Guide for Celery
Celery needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.
| Month | Celery Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.8" | 0" | ❄️ Dormant |
| Feb | — | 4.1" | 0" | ❄️ Dormant |
| Mar | — | 3.5" | 0" | ❄️ Dormant |
| Apr | 5.6" | 2.3" | 3.3" | 🚿 Regular watering |
| May | 5.6" | 2.3" | 3.3" | 🚿 Regular watering |
| Jun | 5.6" | 1.3" | 4.3" | 🚿 Regular watering |
| Jul | 5.6" | 0.6" | 5" | 🚿 Regular watering |
| Aug | 5.6" | 0.7" | 4.9" | 🚿 Regular watering |
| Sep | 5.6" | 1.6" | 4" | 🚿 Regular watering |
| Oct | 5.6" | 2.9" | 2.7" | 💧 Light 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.
Celery 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.
Celery Planting Timeline — Multnomah County, OR
Celery 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 | July 7 | Jul 7 – Sep 1 |
| 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 | — |
| July | Harvest |
| August | Harvest |
| September | Fall Sowing Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.3"/week · 2-3 times/week
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
196 days in Multnomah County
Growing Tips for Celery in Multnomah County
Direct sow Celery outdoors after April 14 in Multnomah County when soil has warmed and frost danger has passed.
Common pests for Celery in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 10-12 weeks before last frost. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder flavor.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Celery in Other Locations
Frequently Asked Questions
When should I plant Celery in Multnomah County, OR?
Multnomah County is in Zone 9a with an average last frost of April 14. Plan your Celery 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.