Blog

When to plant Sunflower in Oldham County County,

Oldham County County's climate puts the Sunflower spring window between April 10 and May 1. time plantings around the expected last-frost window for best survival.

When to Plant Sunflower in Oldham County, KY

Oldham County, Kentucky Zone 6b June

Top priorities for Oldham County, Kentucky gardeners in June

Here's what deserves your attention in Oldham County, Kentucky this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost April 10
Avg. first frost October 22
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
July prep starts now
  • First harvests: sunflower

Instant PDF download. No spam, unsubscribe any time.

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.

Oldham County, Kentucky is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 22, giving you a growing season of approximately 195 days.

At an elevation of 3,065 feet, Oldham County receives approximately 53.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Sunflower during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Oldham County, KY (Zone 6b) Moderate season
195 days
Last Spring Frost April 10
195 growing days
First Fall Frost October 22

Oldham County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.5

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (21 days to spare)
Start indoors: Mar 14 Transplant: Apr 4 🌸 Bloom: Jun 27 – Sep 26
Recommended (50%) ✓ Fits season (20 days to spare)
Start indoors: Mar 20 Transplant: Apr 10 🌸 Bloom: Jul 3 – Oct 2
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Apr 9 Transplant: Apr 30 🌸 Bloom: Jul 23 – 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 Oldham County

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

Soil pH

Your soil pH (5.2–6.5) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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 195-day season

Sow every 8 weeks. Last sowing by Jul 14 to harvest before frost.

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
1.2″/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 3.7" 0" ❄️ Dormant
Feb 4" 0" ❄️ Dormant
Mar 5.4" 0" ❄️ Dormant
Apr 2.2" 3.9" 0" ✅ Rainfall sufficient
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 5.3" 0" ✅ Rainfall sufficient
Jul 2.2" 5.6" 0" ✅ Rainfall sufficient
Aug 2.2" 5.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.7" 0" ✅ Rainfall sufficient
Oct 2.2" 3.7" 0" ✅ Rainfall sufficient
Nov 3.4" 0" ❄️ Dormant
Dec 4.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Oldham 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 2,827 GDD Excellent fit

Sunflower Planting Timeline — Oldham County, KY

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors April 10 Apr 10 – Apr 24
Direct Sow April 10 Apr 10 – May 1
Bloom July 3 Jul 3 – Oct 2

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: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

195 days in Oldham County

Growing Tips for Sunflower in Oldham County

Direct sow Sunflower outdoors after April 10 in Oldham 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 Oldham County, KY?

Oldham County is in Zone 6b with an average last frost of April 10. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Oldham County, KY?

Oldham County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 22.

When should I plant Sunflower in Oldham County, ?

In Oldham County, , plant Sunflower after the last frost (around April 10) and before the first frost (around October 22). Best results when soil holds above 50°F.

What growing zone is Oldham County, for Sunflower?

Oldham County sits in USDA Zone 6b. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.

Can Sunflower grow in Oldham County's climate?

Yes — Sunflower grows well in Oldham County's temperate climate. Oldham County averages a 195-day frost-free season, with last frost around April 10 and first frost around October 22.

🌱

Your Oldham County Garden Planner — Free

A 22-page printable planner built for Oldham County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Oldham County, KY. 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.