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When to Plant Onion in Holt County, NE

Holt County, Nebraska Zone 5a May

May in Holt County, Nebraska — your action list

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

Avg. last frost May 4
Avg. first frost October 6
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Set out onion seedlings

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

Get ahead of June
  • 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.

Holt County, Nebraska is in USDA Zone 5a. The average last spring frost is May 4 and the first fall frost is October 6, giving you a growing season of approximately 155 days.

At an elevation of 708 feet, Holt County receives approximately 28 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.

Holt County, NE (Zone 5a) Moderate season
155 days
Last Spring Frost May 4
155 growing days
First Fall Frost October 6

Holt County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jul 28 – Sep 15
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Aug 3 – Sep 21
Safe Start (90%) ✓ Fits season (11 days to spare)
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: Aug 17 – Oct 5

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 Holt County

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

Soil pH

Your soil pH (6.7–7.7) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Onion.

How to Plant Onion

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 399 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 0.7" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 3.2" 1.1" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Holt 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 1,550 GDD Excellent fit

Onion Planting Timeline — Holt County, NE

Onion Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 4 May 4 – May 18
Direct Sow April 20 Apr 20 – May 11
Harvest August 3 Aug 3 – Sep 21
Fall Sowing July 28 Jul 28 – Aug 11

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5a

📆 Growing Season

155 days in Holt County

Growing Tips for Onion in Holt County

Direct sow Onion outdoors after May 04 in Holt 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.

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 Holt County, NE?

Holt County is in Zone 5a with an average last frost of May 4. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Holt County, NE?

Holt County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is May 4 and first fall frost is October 6.

🌱

Your Holt County Garden Planner — Free

A 24-page printable planner built for Holt County (Zone 5a). 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 Holt County, NE. 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.