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When to Plant Petunia in Summit County, OH

Summit County, Ohio Zone 6b June

June to-do list for Summit County, Ohio

Your Summit County, Ohio garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost May 4
Avg. first frost October 13
Soil temp (4") 66°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
  1. Time to start petunia inside

    Label every cell. You will absolutely forget which is which otherwise.

Get ahead of July
  • First harvests: petunia

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Petunias (Petunia x hybrida) are warm-season tender annuals prized for their prolific, trumpet-shaped blooms in nearly every color. They perform from hanging baskets to garden borders and bloom continuously from late spring until frost, provided spent flowers are removed regularly.

Summit County, Ohio is in USDA Zone 6b. The average last spring frost is May 4 and the first fall frost is October 13, giving you a growing season of approximately 162 days.

At an elevation of 1,309 feet, Summit County receives approximately 33.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Petunia during the growing season.

Annual Blooms in Summer Pollinator-friendly Fragrant
Summit County, OH (Zone 6b) Moderate season
162 days
Last Spring Frost May 4
162 growing days
First Fall Frost October 13

Summit County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Petunia Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 3 Transplant: May 5 🌸 Bloom: Jul 14 – Oct 27
Recommended (50%) ✗ May not fit
Start indoors: Mar 9 Transplant: May 11 🌸 Bloom: Jul 20 – Nov 2
Safe Start (90%) ✗ May not fit
Start indoors: Mar 27 Transplant: May 29 🌸 Bloom: Aug 7 – Nov 20

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 Summit County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Petunia's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Petunia will thrive.

How to Plant Petunia

12"
Between Plants
12"
Between Rows

Succession Planting Petunia

2
successive plantings in your 162-day season

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

Petunia Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 232 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Petunia

Petunia needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Petunia Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 3.6" 0.7" 💧 Light watering
Jul 4.3" 3.2" 1.1" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 2.6" 1.7" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Summit County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Petunia 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.

Petunia needs ~1,280 GDD — county provides 2,592 GDD Excellent fit

Petunia Planting Timeline — Summit County, OH

Petunia Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors May 11 May 11 – May 25
Bloom July 20 Jul 20 – Nov 2

· 12" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors
June
July Bloom
August Bloom
September Bloom
October Bloom
November Bloom
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

162 days in Summit County

Growing Tips for Petunia in Summit County

Direct sow Petunia outdoors after May 04 in Summit County when soil has warmed and frost danger has passed.

Common pests for Petunia in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8–10 weeks before last frost; seeds need light to germinate — press onto moist mix surface, do not cover. Transplant after last frost once nights stay above 50°F. Pinch back leggy plants mid-summer to encourage bushy re-bloom. Wave/spreading types tolerate light shade but bloom less. Feed every 2 weeks with balanced fertilizer once established.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Petunia in Summit County, OH?

Summit County is in Zone 6b with an average last frost of May 4. Plan your Petunia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Summit County, OH?

Summit County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is May 4 and first fall frost is October 13.

🌱

Your Summit County Garden Planner — Free

A 22-page printable planner built for Summit 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 Summit County, OH. 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.