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When to Plant Sunflower in Cuyahoga County, OH

Cuyahoga County, Ohio Zone 6b May

This month in Cuyahoga County, Ohio

We've pulled the most time-sensitive tasks for Cuyahoga County, Ohio this May and put them front and centre. Tackle them in order.

Avg. last frost April 29
Avg. first frost October 20
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Plant out sunflower

    Your last frost (April 29) has passed. These warm-season crops can handle outdoor soil now.

  2. Outdoor sowing time: sunflower

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Looking ahead to June
  • 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.

Cuyahoga County, Ohio is in USDA Zone 6b. The average last spring frost is April 29 and the first fall frost is October 20, giving you a growing season of approximately 174 days.

At an elevation of 530 feet, Cuyahoga County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Sunflower during the growing season.

Cuyahoga County, OH (Zone 6b) Moderate season
174 days
Last Spring Frost April 29
174 growing days
First Fall Frost October 20
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Cuyahoga County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (38 days to spare)
Start indoors: Mar 1 Transplant: May 10 🍅 Harvest: Jul 19 – Sep 6
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Mar 4 Transplant: May 13 🍅 Harvest: Jul 22 – Sep 9
Safe Start (90%) ✓ Fits season (39 days to spare)
Start indoors: Mar 22 Transplant: May 31 🍅 Harvest: Aug 9 – Sep 27

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 Cuyahoga County

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

Soil pH

Your soil pH (6.1–6.8) is within Sunflower's preferred range (6.0–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Sunflower.

Organic Matter

Organic matter is moderate (3.8%). 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 174-day season

Sow every 8 weeks. Last sowing by Jul 12 to harvest before frost.

Plant 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 2.8" 0" ❄️ Dormant
Apr 2.2" 3" 0" ✅ Rainfall sufficient
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.5" 0" ✅ Rainfall sufficient
Jul 2.2" 3.9" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.4" 0" ✅ Rainfall sufficient
Oct 2.2" 2.7" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cuyahoga 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 ~1,424 GDD — county provides 2,914 GDD Excellent fit

Sunflower Planting Timeline — Cuyahoga County, OH

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors May 13 May 13 – May 27
Direct Sow May 6 May 6 – May 27
Harvest July 22 Jul 22 – Sep 9

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July Harvest
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 6b

📆 Growing Season

174 days in Cuyahoga County

Growing Tips for Sunflower in Cuyahoga County

Direct sow Sunflower outdoors after April 29 in Cuyahoga 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 Cuyahoga County, OH?

Cuyahoga County is in Zone 6b with an average last frost of April 29. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cuyahoga County, OH?

Cuyahoga County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 29 and first fall frost is October 20.

🌱

Your Cuyahoga County Garden Planner — Free

A 24-page printable planner built for Cuyahoga 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.

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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 Cuyahoga County, OH. 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.