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When to Plant Sunflower in Otoe County, NE

Otoe County, Nebraska Zone 6a May

Your May game plan for Otoe County, Nebraska

Here's what deserves your attention in Otoe County, Nebraska this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost April 24
Avg. first frost October 10
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
  1. Harden off and plant sunflower

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Scatter sunflower into prepared beds

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

June will be here before you know it — start on
  • Starting indoors: sunflower

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Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Otoe County, Nebraska is in USDA Zone 6a. The average last spring frost is April 24 and the first fall frost is October 10, giving you a growing season of approximately 169 days.

At an elevation of 550 feet, Otoe County receives approximately 27.1 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Sunflower to ensure they mature before fall.

Otoe County, NE (Zone 6a) Moderate season
169 days
Last Spring Frost April 24
169 growing days
First Fall Frost October 10
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Otoe County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Start indoors: Feb 24 Transplant: May 5 🍅 Harvest: Jul 14 – Sep 1
Recommended (50%) ✓ Fits season (36 days to spare)
Start indoors: Feb 27 Transplant: May 8 🍅 Harvest: Jul 17 – Sep 4
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: Mar 16 Transplant: May 25 🍅 Harvest: Aug 3 – Sep 21

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 Otoe County

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

Soil pH

Your soil pH (6.5–7.3) is within Sunflower's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

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

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

2
successive plantings in your 169-day season

Sow every 8 weeks. Last sowing by Jul 02 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan 0.7" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.2" 2.8" 0" ✅ Rainfall sufficient
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4.7" 0" ✅ Rainfall sufficient
Jul 2.2" 3.7" 0" ✅ Rainfall sufficient
Aug 2.2" 3" 0" ✅ Rainfall sufficient
Sep 2.2" 2.6" 0" ✅ Rainfall sufficient
Oct 2.2" 1.6" 0.6" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

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

Sunflower 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.

Sunflower needs ~1,041 GDD — county provides 2,070 GDD Excellent fit

Sunflower Planting Timeline — Otoe County, NE

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest July 17 Jul 17 – Sep 4

Plant 1" deep · 18" apart · Rows 30" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

169 days in Otoe County

Growing Tips for Sunflower in Otoe County

Direct sow Sunflower outdoors after April 24 in Otoe County when soil has warmed and frost danger has passed.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Otoe County, NE?

Otoe County is in Zone 6a with an average last frost of April 24. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Otoe County, NE?

Otoe County, Nebraska is in USDA Hardiness Zone 6a. The average last spring frost is April 24 and first fall frost is October 10.

🌱

Your Otoe County Garden Planner — Free

A 24-page printable planner built for Otoe 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.

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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 Otoe 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.