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When to plant Petunia in Morrison County County,

In Morrison County County, Petunia is a spring-only crop. Plant May 18–June 1 once soil hits 50°F.

When to Plant Petunia in Morrison County, MN

Morrison County, Minnesota Zone 4a June

Your June planting checklist for Morrison County, Minnesota

June is a pivotal month for Morrison County, Minnesota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 4
Avg. first frost October 6
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 15.5 hrs
Coming up in July — start thinking about
  • Starting indoors: 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.

Morrison County, Minnesota is in USDA Zone 4a. The average last spring frost is May 4 and the first fall frost is October 6, giving you a growing season of approximately 155 days.

At an elevation of 1,070 feet, Morrison County receives approximately 40 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Petunia to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly Fragrant
Morrison County, MN (Zone 4a) Moderate season
155 days
Last Spring Frost May 4
155 growing days
First Fall Frost October 6

Morrison County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.1

Drainage

Well Drained

Petunia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Feb 23 Transplant: May 11 🌸 Bloom: Jul 27 – Sep 28
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Mar 2 Transplant: May 18 🌸 Bloom: Aug 3 – Oct 5
Safe Start (90%) ✗ May not fit
Start indoors: Mar 18 Transplant: Jun 3 🌸 Bloom: Aug 19 – 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 Morrison County

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

Soil pH

Your soil pH (5.7–7.1) overlaps with Petunia's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — Petunia will thrive.

How to Plant Petunia

12"
Between Plants
12"
Between Rows

Succession Planting Petunia

2
successive plantings in your 155-day season

Sow every 8 weeks. Last sowing by Jul 08 to harvest before frost.

Petunia Water Budget

Plant needs
1.0″/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 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 1.4" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 4.3" 5" 0" ✅ Rainfall sufficient
Jun 4.3" 5.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Morrison 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 ~800 GDD — county provides 1,550 GDD Excellent fit

Petunia Planting Timeline — Morrison County, MN

Petunia Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors May 18 May 18 – Jun 1
Bloom August 3 Aug 3 – Oct 5

· 12" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

155 days in Morrison County

Growing Tips for Petunia in Morrison County

Direct sow Petunia outdoors after May 04 in Morrison 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 Morrison County, MN?

Morrison County is in Zone 4a 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 Morrison County, MN?

Morrison County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 4 and first fall frost is October 6.

When should I plant Petunia in Morrison County, ?

In Morrison County, , plant Petunia after the last frost (around May 4) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Morrison County, for Petunia?

Morrison County sits in USDA Zone 4a. Petunia grows reliably in zones 2a through 11b, so it's a good fit here.

Can Petunia grow in Morrison County's climate?

Yes — Petunia grows well in Morrison County's temperate climate. Morrison County averages a 155-day frost-free season, with last frost around May 4 and first frost around October 6.

🌱

Your Morrison County Garden Planner — Free

A 22-page printable planner built for Morrison County (Zone 4a). 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 Morrison County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

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