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When to Plant Sunflower in Greeley County, NE

Greeley County, Nebraska Zone 5a June

Your June game plan for Greeley County, Nebraska

June is a pivotal month for Greeley County, Nebraska gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 27
Avg. first frost October 9
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15 hrs
Coming up in July — start thinking about
  • First harvests: sunflower

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Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.

Greeley County, Nebraska is in USDA Zone 5a. The average last spring frost is April 27 and the first fall frost is October 9, giving you a growing season of approximately 165 days.

At an elevation of 1,040 feet, Greeley County receives approximately 30.7 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.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Greeley County, NE (Zone 5a) Moderate season
165 days
Last Spring Frost April 27
165 growing days
First Fall Frost October 9

Greeley County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.4

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Start indoors: Apr 1 Transplant: Apr 29 🌸 Bloom: Jul 22 – Sep 30
Recommended (50%) ✓ Fits season (4 days to spare)
Start indoors: Apr 6 Transplant: May 4 🌸 Bloom: Jul 27 – Oct 5
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: Apr 23 Transplant: May 21 🌸 Bloom: Aug 13 – Oct 22

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 Greeley County

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

Soil pH

Your soil pH (6.2–7.4) is within Sunflower's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Sunflower will thrive.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Sunflower

2
successive plantings in your 165-day season

Sow every 8 weeks. Last sowing by Jul 01 to harvest before frost.

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/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 1.1" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.2" 3.6" 0" ✅ Rainfall sufficient
May 2.2" 4.1" 0" ✅ Rainfall sufficient
Jun 2.2" 4.4" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 4.2" 0" ✅ Rainfall sufficient
Sep 2.2" 2.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.2" 0" ✅ Rainfall sufficient
Nov 1.1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Greeley 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 2,021 GDD Excellent fit

Sunflower Planting Timeline — Greeley County, NE

Sunflower Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 4 May 4 – May 18
Direct Sow May 4 May 4 – May 25
Bloom July 27 Jul 27 – Oct 5

Plant 1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

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 5a

📆 Growing Season

165 days in Greeley County

Growing Tips for Sunflower in Greeley County

Direct sow Sunflower outdoors after April 27 in Greeley 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 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Pole_beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Greeley County, NE?

Greeley County is in Zone 5a with an average last frost of April 27. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Greeley County, NE?

Greeley County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is April 27 and first fall frost is October 9.

🌱

Your Greeley County Garden Planner — Free

A 22-page printable planner built for Greeley 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 Greeley 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.