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When to Plant Scallions in Josephine County, OR

Josephine County, Oregon Zone 8b May

What to do in May

Welcome to May in Zone 8b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 22
Avg. first frost October 20
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.4 hrs
  1. Fire up the seed-starting tray: scallions

    Label every cell. You will absolutely forget which is which otherwise.

Coming up in June — start thinking about
  • First harvests: scallions

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Scallions (green onions) are mild-flavored alliums harvested for their slender green tops and white bases. They are quick-growing and perfect for succession planting.

Josephine County, Oregon is in USDA Zone 8b. The average last spring frost is April 22 and the first fall frost is October 20, giving you a growing season of approximately 181 days.

At an elevation of 340 feet, Josephine County receives approximately 52.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Scallions during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Scallions root diseases.

Josephine County, OR (Zone 8b) Moderate season
181 days
Last Spring Frost April 22
181 growing days
First Fall Frost October 20

Josephine County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (99 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jun 4 – Jul 2
Recommended (50%) ✓ Fits season (97 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jun 17 – Jul 15
Safe Start (90%) ✓ Fits season (109 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jul 7 – Aug 4

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 Josephine County

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

Soil pH

Your soil pH (5.7–6.2) is more acidic than Scallions prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Scallions will thrive.

How to Plant Scallions

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Scallions

4
successive plantings in your 181-day season

Sow every 5.7 weeks. Last sowing by Aug 11 to harvest before frost.

For a dedicated fall crop, sow by Aug 11.

Plant Water Budget

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

Monthly Watering Guide for Scallions

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

Month Scallions Needs Rainfall You Supplement Action
Jan 8.4" 0" ❄️ Dormant
Feb 6.6" 0" ❄️ Dormant
Mar 6.2" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 2" 2.3" 🚿 Regular watering
Jul 4.3" 0.8" 3.5" 🚿 Regular watering
Aug 4.3" 0.9" 3.4" 🚿 Regular watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 4.4" 0" ✅ Rainfall sufficient
Nov 7.4" 0" ❄️ Dormant
Dec 8.2" 0" ❄️ Dormant

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

Scallions 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.

Scallions needs ~1,050 GDD — county provides 3,167 GDD Excellent fit

Scallions Planting Timeline — Josephine County, OR

Scallions Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 8 Apr 8 – Apr 29
Harvest June 17 Jun 17 – Jul 15
Fall Sowing August 11 Aug 11 – Aug 25

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors
June Harvest
July Harvest
August Fall Sowing
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

181 days in Josephine County

Growing Tips for Scallions in Josephine County

Direct sow Scallions outdoors after April 22 in Josephine County when soil has warmed and frost danger has passed.

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

General growing tips

Direct sow every 3 weeks for continuous harvest. Thin to 1 inch apart or grow in clusters. Harvest when pencil-thick by pulling or cutting at soil level.

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 Scallions in Josephine County, OR?

Josephine County is in Zone 8b with an average last frost of April 22. Plan your Scallions planting based on this frost date — see the calendar above for exact timing.

What planting zone is Josephine County, OR?

Josephine County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 22 and first fall frost is October 20.

🌱

Your Josephine County Garden Planner — Free

A 24-page printable planner built for Josephine County (Zone 8b). 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 Josephine 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.