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When to Plant Sunflower in Jefferson County, WV

Jefferson County, West Virginia Zone 7a May

May in Jefferson County, West Virginia — your action list

May is a pivotal month for Jefferson County, West Virginia gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 20
Avg. first frost October 23
Soil temp (4") 55°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Harden off and plant sunflower

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

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.

Jefferson County, West Virginia is in USDA Zone 7a. The average last spring frost is April 20 and the first fall frost is October 23, giving you a growing season of approximately 186 days.

At an elevation of 3,548 feet, Jefferson County receives approximately 48 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Sunflower during the growing season.

Jefferson County, WV (Zone 7a) Moderate season
186 days
Last Spring Frost April 20
186 growing days
First Fall Frost October 23
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Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Feb 23 Transplant: Apr 27 🍅 Harvest: Jul 6 – Aug 24
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Mar 2 Transplant: May 4 🍅 Harvest: Jul 13 – Aug 31
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Mar 23 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 Jefferson County

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

Soil pH

Your soil pH (5.5–7.0) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Sunflower prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Sunflower.

How to Plant Sunflower

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

Succession Planting Sunflower

3
successive plantings in your 186-day season

Sow every 8 weeks. Last sowing by Jul 15 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/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 4.1" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 4.6" 0" ❄️ Dormant
Apr 2.2" 4.1" 0" ✅ Rainfall sufficient
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4" 0" ✅ Rainfall sufficient
Jul 2.2" 4.7" 0" ✅ Rainfall sufficient
Aug 2.2" 4.1" 0" ✅ Rainfall sufficient
Sep 2.2" 4.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.6" 0" ✅ Rainfall sufficient
Nov 3.6" 0" ❄️ Dormant
Dec 4.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jefferson 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 ~1,551 GDD — county provides 3,394 GDD Excellent fit

Sunflower Planting Timeline — Jefferson County, WV

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors May 4 May 4 – May 18
Direct Sow April 27 Apr 27 – May 18
Harvest July 13 Jul 13 – Aug 31

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September
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: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

186 days in Jefferson County

Growing Tips for Sunflower in Jefferson County

Direct sow Sunflower outdoors after April 20 in Jefferson 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 Jefferson County, WV?

Jefferson County is in Zone 7a with an average last frost of April 20. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, WV?

Jefferson County, West Virginia is in USDA Hardiness Zone 7a. The average last spring frost is April 20 and first fall frost is October 23.

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Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson 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 Jefferson County, WV. 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.