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When to Plant Onion in Jefferson 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.

Jefferson County, Nebraska is in USDA Zone 6a. The average last spring frost is April 22 and the first fall frost is October 13, giving you a growing season of approximately 174 days.

At an elevation of 727 feet, Jefferson County receives approximately 22 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.

Jefferson County, NE (Zone 6a) Moderate season
174 days
Last Spring Frost April 22
174 growing days
First Fall Frost October 13

Jefferson County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Onion Planting Timeline — Jefferson County, NE

Onion 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 July 22 Jul 22 – Sep 9
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 Start Indoors 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 6a

📆 Growing Season

174 days in Jefferson County

Growing Tips for Jefferson 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 Jefferson County, NE?

Jefferson County is in Zone 6a with an average last frost of April 22. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, NE?

Jefferson County, Nebraska is in USDA Hardiness Zone 6a. The average last spring frost is April 22 and first fall frost is October 13.

🌱

Your Jefferson County Garden Planner — Free

A 22-page printable planner built for Jefferson 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.

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 Jefferson 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.