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When to Plant Onion in McIntosh County, ND

McIntosh County, North Dakota Zone 4b May

May in McIntosh County, North Dakota — your action list

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

Avg. last frost May 12
Avg. first frost September 28
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Harden off and plant onion

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Put onion seeds straight in the ground

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

To set up a strong June, finish these tasks
  • Starting indoors: onion

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Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

McIntosh County, North Dakota is in USDA Zone 4b. The average last spring frost is May 12 and the first fall frost is September 28, giving you a growing season of approximately 139 days.

At an elevation of 659 feet, McIntosh County receives approximately 21.2 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Onion to ensure they mature before fall.

McIntosh County, ND (Zone 4b) Short season
139 days
Last Spring Frost May 12
139 growing days
First Fall Frost September 28

McIntosh County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Mar 23 Transplant: May 4 🍅 Harvest: Aug 3 – Sep 21
Recommended (50%) ✗ May not fit
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Aug 11 – Sep 29
Safe Start (90%) ✓ Fits season (4 days to spare)
Start indoors: Apr 9 Transplant: May 21 🍅 Harvest: Aug 20 – Oct 8

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 McIntosh County

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

Soil pH

Your soil pH (6.6–7.2) overlaps with Onion's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in McIntosh County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.2%) — Onion will thrive.

How to Plant Onion

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 534 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Onion

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

Month Onion Needs Rainfall You Supplement Action
Jan 0.6" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 3.6" 0.7" 💧 Light watering
Jul 4.3" 2.7" 1.6" 💧 Light watering
Aug 4.3" 2.2" 2.1" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.7" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

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

Onion 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.

Onion needs ~1,050 GDD — county provides 1,390 GDD Excellent fit

Onion Planting Timeline — McIntosh County, ND

Onion Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 – Apr 14
Transplant Outdoors May 12 May 12 – May 26
Direct Sow May 5 May 5 – May 26
Harvest August 11 Aug 11 – Sep 29
Fall Sowing July 6 Jul 6 – Jul 20

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

139 days in McIntosh County

Growing Tips for Onion in McIntosh County

Direct sow Onion outdoors after May 12 in McIntosh County when soil has warmed and frost danger has passed.

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

McIntosh County receives only 21" of rain annually. Onion needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in McIntosh County, ND?

McIntosh County is in Zone 4b with an average last frost of May 12. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is McIntosh County, ND?

McIntosh County, North Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 12 and first fall frost is September 28.

🌱

Your McIntosh County Garden Planner — Free

A 24-page printable planner built for McIntosh County (Zone 4b). 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 McIntosh County, ND. 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.