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When to Plant Onion in Seward County, NE

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.

Seward County, Nebraska is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.

At an elevation of 527 feet, Seward County receives approximately 24.2 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Onion to ensure they mature before fall.

Seward County, NE (Zone 5b) Moderate season
175 days
Last Spring Frost April 21
175 growing days
First Fall Frost October 13

Seward County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Onion Planting Timeline — Seward County, NE

Onion Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 7 Apr 7 – Apr 28
Harvest July 21 Jul 21 – Sep 8
Fall Sowing August 4 Aug 4 – Aug 18

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Seward County

Growing Tips for Seward County

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 Seward County, NE?

Seward County is in Zone 5b with an average last frost of April 21. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Seward County, NE?

Seward County, Nebraska is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.

🌱

Your Seward County Garden Planner — Free

A 22-page printable planner built for Seward County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Seward County, NE. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.