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When to plant Sunflower in Hempstead County, AR

In Zone 8a (Hempstead County), direct-sow Sunflower between March 14 and April 4 for spring, after the March 21 last-frost mark.

When to Plant Sunflower in Hempstead County, AR

Hempstead County, Arkansas Zone 8a June

Your June game plan for Hempstead County, Arkansas

We've pulled the most time-sensitive tasks for Hempstead County, Arkansas this June and put them front and centre. Tackle them in order.

Avg. last frost March 21
Avg. first frost November 12
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.2 hrs
  1. It's harvest week for sunflower

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

July prep starts now
  • 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.

Hempstead County, Arkansas is in USDA Zone 8a. The average last spring frost is March 21 and the first fall frost is November 12, giving you a growing season of approximately 236 days.

At an elevation of 1,302 feet, Hempstead County receives approximately 48.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Sunflower during the growing season.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Hempstead County, AR (Zone 8a) Long season
236 days
Last Spring Frost March 21
236 growing days
First Fall Frost November 12

Hempstead County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7.1

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Feb 19 Transplant: Mar 5 🌸 Bloom: May 28 – Oct 1
Recommended (50%) ✓ Fits season (33 days to spare)
Start indoors: Feb 28 Transplant: Mar 14 🌸 Bloom: Jun 6 – Oct 10
Safe Start (90%) ✓ Fits season (26 days to spare)
Start indoors: Mar 24 Transplant: Apr 7 🌸 Bloom: Jun 30 – Nov 3

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 Hempstead County

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

Soil pH

Your soil pH (5.5–7.1) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Sunflower.

How to Plant Sunflower

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

Succession Planting Sunflower

3
successive plantings in your 236-day season

Sow every 8 weeks. Last sowing by Aug 04 to harvest before frost.

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 4.1" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 2.2" 4.2" 0" ✅ Rainfall sufficient
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 4.2" 0" ✅ Rainfall sufficient
Jun 2.2" 3.8" 0" ✅ Rainfall sufficient
Jul 2.2" 4.8" 0" ✅ Rainfall sufficient
Aug 2.2" 4.5" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
Oct 2.2" 3.6" 0" ✅ Rainfall sufficient
Nov 2.2" 4.3" 0" ✅ Rainfall sufficient
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Hempstead 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 ~1,360 GDD — county provides 3,776 GDD Excellent fit

Sunflower Planting Timeline — Hempstead County, AR

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors March 14 Mar 14 – Mar 28
Direct Sow March 14 Mar 14 – Apr 4
Bloom June 6 Jun 6 – Oct 10

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April Direct Sow
May
June Bloom
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: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

236 days in Hempstead County

Growing Tips for Sunflower in Hempstead County

Direct sow Sunflower outdoors after March 21 in Hempstead 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 Hempstead County, AR?

Hempstead County is in Zone 8a with an average last frost of March 21. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hempstead County, AR?

Hempstead County, Arkansas is in USDA Hardiness Zone 8a. The average last spring frost is March 21 and first fall frost is November 12.

When should I plant Sunflower in Hempstead County, AR?

In Hempstead County, AR, plant Sunflower after the last frost (around March 21) and before the first frost (around November 12). Best results when soil holds above 50°F.

What growing zone is Hempstead County, AR for Sunflower?

Hempstead County sits in USDA Zone 8a. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.

Can Sunflower grow in Hempstead County's climate?

Yes — Sunflower grows well in Hempstead County's temperate climate. Hempstead County averages a 236-day frost-free season, with last frost around March 21 and first frost around November 12.

🌱

Your Hempstead County Garden Planner — Free

A 22-page printable planner built for Hempstead County (Zone 8a). 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 Hempstead County, AR. 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.