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When to Plant Sunflower in Sheridan County, NE

Sheridan County, Nebraska Zone 5a May

Sheridan County, Nebraska gardeners: here's your May plan

Here's what deserves your attention in Sheridan County, Nebraska this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost May 14
Avg. first frost September 28
Soil temp (4") 56°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Harden off and plant sunflower

    Frost risk is low now in Sheridan County, Nebraska. If you've been covering beds overnight, you can stop.

  2. Direct-sow sunflower

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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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.

Sheridan County, Nebraska is in USDA Zone 5a. The average last spring frost is May 14 and the first fall frost is September 28, giving you a growing season of approximately 137 days.

At an elevation of 1,111 feet, Sheridan County receives approximately 25.2 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Sunflower to ensure they mature before fall.

Sheridan County, NE (Zone 5a) Short season
137 days
Last Spring Frost May 14
137 growing days
First Fall Frost September 28
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Sheridan County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 16 Transplant: May 25 🍅 Harvest: Aug 3 – Sep 21
Recommended (50%) ✓ Fits season (4 days to spare)
Start indoors: Mar 19 Transplant: May 28 🍅 Harvest: Aug 6 – Sep 24
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Mar 29 Transplant: Jun 7 🍅 Harvest: Aug 16 – Oct 4

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 Sheridan County

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

Soil pH

Your soil pH (6.7–7.3) is within Sunflower's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

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

How to Plant Sunflower

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

Succession Planting Sunflower

2
successive plantings in your 137-day season

Sow every 8 weeks. Last sowing by Jun 20 to harvest before frost.

Plant Water Budget

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

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

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 1.8" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 1.7" 0.5" 💧 Light watering
Jul 2.2" 2.2" 0" ✅ Rainfall sufficient
Aug 2.2" 2.9" 0" ✅ Rainfall sufficient
Sep 2.2" 1.8" 0.4" 💧 Light watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Sheridan 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 ~978 GDD — county provides 1,575 GDD Excellent fit

Sunflower Planting Timeline — Sheridan County, NE

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors May 28 May 28 – Jun 11
Direct Sow May 21 May 21 – Jun 11
Harvest August 6 Aug 6 – Sep 24

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
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 5a

📆 Growing Season

137 days in Sheridan County

Growing Tips for Sunflower in Sheridan County

Direct sow Sunflower outdoors after May 14 in Sheridan 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 Sheridan County, NE?

Sheridan County is in Zone 5a with an average last frost of May 14. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sheridan County, NE?

Sheridan County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is May 14 and first fall frost is September 28.

🌱

Your Sheridan County Garden Planner — Free

A 24-page printable planner built for Sheridan 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 Sheridan 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.