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When to Plant Shallot in Clackamas County, OR

Clackamas County, Oregon Zone 9a May

Your May game plan for Clackamas County, Oregon

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Clackamas County, Oregon.

Avg. last frost April 14
Avg. first frost October 28
Soil temp (4") 73°F
Watering Moderate
Pest pressure High
Daylight 14.7 hrs
  1. Time to start shallot inside

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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Shallots are a gourmet allium prized for their complex, sweet, and mild flavor. Each bulb multiplies into a cluster, making them easy and rewarding to grow.

Clackamas County, Oregon is in USDA Zone 9a. The average last spring frost is April 14 and the first fall frost is October 28, giving you a growing season of approximately 197 days.

At an elevation of 199 feet, Clackamas County receives approximately 53.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Shallot during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Shallot root diseases.

Clackamas County, OR (Zone 9a) Moderate season
197 days
Last Spring Frost April 14
197 growing days
First Fall Frost October 28
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Clackamas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (57 days to spare)
Start indoors: Mar 7 Transplant: Apr 4 🍅 Harvest: Jul 4 – Aug 22
Recommended (50%) ✓ Fits season (57 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🍅 Harvest: Jul 14 – Sep 1
Safe Start (90%) ✓ Fits season (61 days to spare)
Start indoors: Apr 9 Transplant: May 7 🍅 Harvest: Aug 6 – Sep 24

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 Clackamas County

How your county's soil matches Shallot's growing requirements.

Soil pH

Your soil pH (5.7–6.3) overlaps with Shallot's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.7%) — Shallot will thrive.

How to Plant Shallot

1"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Plant Water Budget

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

Monthly Watering Guide for Shallot

Shallot needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Shallot Needs Rainfall You Supplement Action
Jan 8.3" 0" ❄️ Dormant
Feb 5.3" 0" ❄️ Dormant
Mar 4.8" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 2.1" 2.2" 🚿 Regular watering
Jul 4.3" 0.8" 3.5" 🚿 Regular watering
Aug 4.3" 1" 3.3" 🚿 Regular watering
Sep 4.3" 2.2" 2.1" 💧 Light watering
Oct 4.3" 4.7" 0" ✅ Rainfall sufficient
Nov 8.2" 0" ❄️ Dormant
Dec 8.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clackamas County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Shallot 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.

Shallot needs ~1,444 GDD — county provides 2,708 GDD Excellent fit

Shallot Planting Timeline — Clackamas County, OR

Shallot 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 14 Jul 14 – Sep 1
Fall Sowing September 2 Sep 2 – Sep 16

Plant 1" deep · 6" 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

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

197 days in Clackamas County

Growing Tips for Shallot in Clackamas County

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

Common pests for Shallot in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant sets in fall for spring harvest or early spring for summer harvest. Mulch heavily if overwintering. Harvest when tops brown and dry, then cure for storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Shallot in Clackamas County, OR?

Clackamas County is in Zone 9a with an average last frost of April 14. Plan your Shallot planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clackamas County, OR?

Clackamas County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 14 and first fall frost is October 28.

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Your Clackamas County Garden Planner — Free

A 24-page printable planner built for Clackamas 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 Clackamas 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.