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When to Plant Scallions in Preble County, OH

Preble County, Ohio Zone 6a May

May in the garden — Preble County, Ohio

Here's what deserves your attention in Preble County, Ohio this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost April 24
Avg. first frost October 21
Soil temp (4") 62°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Start scallions indoors

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

Get ahead of June
  • 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.

Preble County, Ohio is in USDA Zone 6a. The average last spring frost is April 24 and the first fall frost is October 21, giving you a growing season of approximately 180 days.

At an elevation of 1,250 feet, Preble County receives approximately 40 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Scallions during the growing season.

Preble County, OH (Zone 6a) Moderate season
180 days
Last Spring Frost April 24
180 growing days
First Fall Frost October 21

Preble County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (97 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jun 10 – Jul 8
Recommended (50%) ✓ Fits season (96 days to spare)
Start indoors: Mar 20 Transplant: Apr 24 🍅 Harvest: Jun 19 – Jul 17
Safe Start (90%) ✓ Fits season (94 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jul 4 – Aug 1

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 Preble County

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

Soil pH

Your soil pH (6.0–6.9) is within Scallions's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Scallions.

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 180-day season

Sow every 5.7 weeks. Last sowing by Aug 12 to harvest before frost.

For a dedicated fall crop, sow by Aug 12.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 128 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 4.1" 0.2" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Preble 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 ~1,095 GDD — county provides 3,285 GDD Excellent fit

Scallions Planting Timeline — Preble County, OH

Scallions Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 10 Apr 10 – May 1
Harvest June 19 Jun 19 – Jul 17
Fall Sowing August 12 Aug 12 – Aug 26

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 Direct Sow
June Harvest
July Harvest
August Fall Sowing
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

180 days in Preble County

Growing Tips for Scallions in Preble County

Direct sow Scallions outdoors after April 24 in Preble 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 Preble County, OH?

Preble County is in Zone 6a with an average last frost of April 24. Plan your Scallions planting based on this frost date — see the calendar above for exact timing.

What planting zone is Preble County, OH?

Preble County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 24 and first fall frost is October 21.

🌱

Your Preble County Garden Planner — Free

A 24-page printable planner built for Preble County (Zone 6a). 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 Preble County, OH. 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.