When to plant Petunia in Mower County, MN
In Mower County, Petunia is a single-season spring crop — there's no second fall window. Plant May 5–May 19 for an 70–90-day harvest, finishing well before the October 7 first frost.
When to Plant Petunia in Mower County, MN
Your June gardening checklist
A quick June briefing for Mower County, Minnesota gardeners — what's urgent, what's next, and what can wait.
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Get petunia seeds going inside
Starting these indoors now means sturdy transplants ready the moment your soil warms up.
Get ahead of July
- First harvests: petunia
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.
Mower County, Minnesota is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 7, giving you a growing season of approximately 162 days.
At an elevation of 577 feet, Mower County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Petunia to ensure they mature before fall.
Mower County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-6.7
Drainage
Well Drained
Petunia Planting Risk Windows
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 Mower County
How your county's soil matches Petunia's growing requirements.
Soil pH
Your soil pH (6.3–6.7) is within Petunia's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Mower County is excellent for Petunia — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.6%) — Petunia will thrive.
How to Plant Petunia
Succession Planting Petunia
Sow every 8 weeks. Last sowing by Jul 09 to harvest before frost.
Petunia Water Budget
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 | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| May | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Jun | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Jul | 4.3" | 3.3" | 1" | 💧 Light watering |
| Aug | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Sep | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Oct | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Mower 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 Planting Timeline — Mower County, MN
Petunia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 24 | Feb 24 – Mar 10 |
| Transplant Outdoors | May 5 | May 5 – May 19 |
| Bloom | July 14 | Jul 14 – Sep 29 |
· 12" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| 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: ideal
🗺️ USDA Zone
Zone 4b
📆 Growing Season
162 days in Mower County
Growing Tips for Petunia in Mower County
Direct sow Petunia outdoors after April 28 in Mower 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 →
Petunia in Other Locations
Frequently Asked Questions
When should I plant Petunia in Mower County, MN?
Mower County is in Zone 4b with an average last frost of April 28. Plan your Petunia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mower County, MN?
Mower County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 7.
When should I plant Petunia in Mower County, MN?
In Mower County, MN, plant Petunia after the last frost (around April 28) and before the first frost (around October 7). Best results when soil holds above 50°F.
What growing zone is Mower County, MN for Petunia?
Mower County sits in USDA Zone 4b. Petunia grows reliably in zones 2a through 11b, so it's a good fit here.
Can Petunia grow in Mower County's climate?
Yes — Petunia grows well in Mower County's temperate climate. Mower County averages a 162-day frost-free season, with last frost around April 28 and first frost around October 7.
Your Mower County Garden Planner — Free
A 22-page printable planner built for Mower County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.