Blog

When to plant Petunia in Edwards County, IL

In Edwards County, Petunia is a single-season spring crop — there's no second fall window. Plant April 16–April 30 for an 70–90-day harvest, finishing well before the October 28 first frost.

When to Plant Petunia in Edwards County, IL

Edwards County, Illinois Zone 6b July

Your July planting checklist for Edwards County, Illinois

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

Avg. last frost April 9
Avg. first frost October 28
Soil temp (4") 80°F
Watering Low
Pest pressure High
Daylight 14.4 hrs
  1. Collect petunia at their peak

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

A few tasks this July that'll pay off in August
  • First harvests: petunia

Instant PDF download. No spam, unsubscribe any time.

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.

Edwards County, Illinois is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 28, giving you a growing season of approximately 202 days.

At an elevation of 1,374 feet, Edwards County receives approximately 35.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Petunia during the growing season.

Annual Blooms in Summer Pollinator-friendly Fragrant
Edwards County, IL (Zone 6b) Long season
202 days
Last Spring Frost April 9
202 growing days
First Fall Frost October 28

Edwards County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Petunia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (20 days to spare)
Start indoors: Feb 5 Transplant: Apr 9 🌸 Bloom: Jun 18 – Oct 1
Recommended (50%) ✓ Fits season (20 days to spare)
Start indoors: Feb 12 Transplant: Apr 16 🌸 Bloom: Jun 25 – Oct 8
Safe Start (90%) ✓ Fits season (26 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🌸 Bloom: Jul 8 – Oct 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 Edwards County

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

Soil pH

Your soil pH (6.0–7.2) overlaps with Petunia's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Petunia will thrive.

How to Plant Petunia

12"
Between Plants
12"
Between Rows

Succession Planting Petunia

3
successive plantings in your 202-day season

Sow every 8 weeks. Last sowing by Jul 30 to harvest before frost.

Petunia Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 475 gal / 100 sq ft

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 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Edwards 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 ~1,100 GDD — county provides 2,777 GDD Excellent fit

Petunia Planting Timeline — Edwards County, IL

Petunia Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Bloom June 25 Jun 25 – Oct 8

· 12" apart · Rows 12" apart

Month-by-Month Timeline

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

202 days in Edwards County

Growing Tips for Petunia in Edwards County

Direct sow Petunia outdoors after April 09 in Edwards 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 Edwards County, IL?

Edwards County is in Zone 6b with an average last frost of April 9. Plan your Petunia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Edwards County, IL?

Edwards County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 28.

When should I plant Petunia in Edwards County, IL?

In Edwards County, IL, plant Petunia after the last frost (around April 9) and before the first frost (around October 28). Best results when soil holds above 50°F.

What growing zone is Edwards County, IL for Petunia?

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

Can Petunia grow in Edwards County's climate?

Yes — Petunia grows well in Edwards County's temperate climate. Edwards County averages a 202-day frost-free season, with last frost around April 9 and first frost around October 28.

🌱

Your Edwards County Garden Planner — Free

A 22-page printable planner built for Edwards 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 Edwards County, IL. 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.