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When to Plant Onion in Becker County, MN

Becker County, Minnesota Zone 4a May

Your May planting checklist for Becker County, Minnesota

Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 15
Avg. first frost September 25
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
  1. Get onion in the ground

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Seed onion outdoors

    Your soil is 51°F — warm enough for these to germinate without babying.

Coming up in June — start thinking about
  • 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.

Becker County, Minnesota is in USDA Zone 4a. The average last spring frost is May 15 and the first fall frost is September 25, giving you a growing season of approximately 133 days.

At an elevation of 729 feet, Becker County receives approximately 35.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Onion to ensure they mature before fall.

Becker County, MN (Zone 4a) Short season
133 days
Last Spring Frost May 15
133 growing days
First Fall Frost September 25

Becker County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Aug 9 – Sep 27
Recommended (50%) ✗ May not fit
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Aug 14 – Oct 2
Safe Start (90%) ✗ May not fit
Start indoors: Apr 15 Transplant: May 27 🍅 Harvest: Aug 26 – Oct 14

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 Becker County

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

Soil pH

Your soil pH (6.1–7.1) overlaps with Onion's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Onion.

Organic Matter

Organic matter is excellent (4.0%) — 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
1.1″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 268 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 1.6" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.1" 0" ❄️ Dormant
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 2.5" 0" ❄️ Dormant
Nov 2.5" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Becker 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 ~892 GDD — county provides 1,130 GDD Good fit

Onion Planting Timeline — Becker County, MN

Onion Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest August 14 Aug 14 – Oct 2
Fall Sowing July 3 Jul 3 – Jul 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

133 days in Becker County

Growing Tips for Onion in Becker County

Direct sow Onion outdoors after May 15 in Becker County when soil has warmed and frost danger has passed.

Your 133.0-day growing season in Becker County is tight for Onion (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

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 Becker County, MN?

Becker County is in Zone 4a with an average last frost of May 15. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Becker County, MN?

Becker County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 15 and first fall frost is September 25.

🌱

Your Becker County Garden Planner — Free

A 24-page printable planner built for Becker County (Zone 4a). 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 Becker County, MN. 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.