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When to plant Sunflower in Stone County, MO

For Stone County, gardeners: plant Sunflower April 16 through May 7 once soil reads 50°F.

When to Plant Sunflower in Stone County, MO

Stone County, Missouri Zone 7a July

July to-do list for Stone County, Missouri

We've pulled the most time-sensitive tasks for Stone County, Missouri this July and put them front and centre. Tackle them in order.

Avg. last frost April 16
Avg. first frost October 20
Soil temp (4") 81°F
Watering Low
Pest pressure High
Daylight 14.3 hrs
  1. Harvest sunflower as they ripen

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Get ahead of August
  • 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.

Stone County, Missouri is in USDA Zone 7a. The average last spring frost is April 16 and the first fall frost is October 20, giving you a growing season of approximately 187 days.

At an elevation of 1,310 feet, Stone County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Sunflower during the growing season.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Stone County, MO (Zone 7a) Moderate season
187 days
Last Spring Frost April 16
187 growing days
First Fall Frost October 20

Stone County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.5

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Start indoors: Mar 20 Transplant: Apr 10 🌸 Bloom: Jul 3 – Oct 9
Recommended (50%) ✓ Fits season (5 days to spare)
Start indoors: Mar 26 Transplant: Apr 16 🌸 Bloom: Jul 9 – Oct 15
Safe Start (90%) ✓ Fits season (6 days to spare)
Start indoors: Apr 9 Transplant: Apr 30 🌸 Bloom: Jul 23 – Oct 29

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 Stone County

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

Soil pH

Your soil pH (5.5–6.5) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). 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 187-day season

Sow every 8 weeks. Last sowing by Jul 12 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
Drought risk

Water stress score is 6/10 — 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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.2" 3.9" 0" ✅ Rainfall sufficient
May 2.2" 4.8" 0" ✅ Rainfall sufficient
Jun 2.2" 5.1" 0" ✅ Rainfall sufficient
Jul 2.2" 4.7" 0" ✅ Rainfall sufficient
Aug 2.2" 4.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 3.6" 0" ✅ Rainfall sufficient
Nov 2.8" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Stone 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 ~1,232 GDD — county provides 2,711 GDD Excellent fit

Sunflower Planting Timeline — Stone County, MO

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 16 Apr 16 – May 7
Bloom July 9 Jul 9 – Oct 15

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7a

📆 Growing Season

187 days in Stone County

Growing Tips for Sunflower in Stone County

Direct sow Sunflower outdoors after April 16 in Stone 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 Stone County, MO?

Stone County is in Zone 7a with an average last frost of April 16. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stone County, MO?

Stone County, Missouri is in USDA Hardiness Zone 7a. The average last spring frost is April 16 and first fall frost is October 20.

When should I plant Sunflower in Stone County, MO?

In Stone County, MO, plant Sunflower after the last frost (around April 16) and before the first frost (around October 20). Best results when soil holds above 50°F.

What growing zone is Stone County, MO for Sunflower?

Stone County sits in USDA Zone 7a. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.

Can Sunflower grow in Stone County's climate?

Yes — Sunflower grows well in Stone County's temperate climate. Stone County averages a 187-day frost-free season, with last frost around April 16 and first frost around October 20.

🌱

Your Stone County Garden Planner — Free

A 22-page printable planner built for Stone County (Zone 7a). 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 Stone County, MO. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.