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When to Plant Cumin in Multnomah County, OR

Multnomah County, Oregon Zone 9a May

Your May gardening checklist

We've pulled the most time-sensitive tasks for Multnomah County, Oregon this May and put them front and centre. Tackle them in order.

Avg. last frost April 14
Avg. first frost October 27
Soil temp (4") 72°F
Watering High
Pest pressure High
Daylight 14.7 hrs
  1. Sow cumin in trays indoors

    Your window is short. These crops want several weeks of indoor growth before they go outside.

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Cumin is a warm-season annual herb whose seeds are one of the most widely used spices globally. It requires a long, hot growing season of 3-4 months.

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 Cumin to ensure they mature before fall.

Multnomah County, OR (Zone 9a) Moderate season
196 days
Last Spring Frost April 14
196 growing days
First Fall Frost October 27
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Multnomah County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Start indoors: Mar 11 Transplant: Apr 1 🍅 Harvest: Jul 15 – Sep 16
Recommended (50%) ✓ Fits season (35 days to spare)
Start indoors: Mar 17 Transplant: Apr 7 🍅 Harvest: Jul 21 – Sep 22
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Apr 11 Transplant: May 2 🍅 Harvest: Aug 15 – Oct 17

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 Cumin's growing requirements.

Soil pH

Your soil pH (5.8–6.3) overlaps with Cumin's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Cumin.

Organic Matter

Organic matter is excellent (4.5%) — Cumin will thrive.

How to Plant Cumin

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Cumin

Cumin needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cumin Needs Rainfall You Supplement Action
Jan 5.8" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 2.2" 2.3" 0" ✅ Rainfall sufficient
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.3" 0.9" 💧 Light watering
Jul 2.2" 0.6" 1.6" 🚿 Regular watering
Aug 2.2" 0.7" 1.5" 🚿 Regular watering
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 2.2" 2.9" 0" ✅ Rainfall sufficient
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.

Cumin 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.

Cumin needs ~1,430 GDD — county provides 2,548 GDD Excellent fit

Cumin Planting Timeline — Multnomah County, OR

Cumin Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 7 Apr 7 – Apr 21
Direct Sow March 24 Mar 24 – Apr 14
Harvest July 21 Jul 21 – Sep 22
Fall Sowing September 1 Sep 1 – Sep 15

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

196 days in Multnomah County

Growing Tips for Cumin in Multnomah County

Direct sow Cumin outdoors after April 14 in Multnomah County when soil has warmed and frost danger has passed.

Common pests for Cumin 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 4 weeks before last frost. Transplant after all danger of frost. Harvest when seed heads turn brown. Requires consistent warmth for proper seed development.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cumin in Multnomah County, OR?

Multnomah County is in Zone 9a with an average last frost of April 14. Plan your Cumin 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.

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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.

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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 Multnomah County, OR. 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.