When to Plant Petunia in Wasatch County, UT
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.
Wasatch County, Utah is in USDA Zone 6a. The average last spring frost is May 19 and the first fall frost is September 26, giving you a growing season of approximately 130 days.
At an elevation of 8,190 feet, Wasatch County receives approximately 16.6 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Petunia during the growing season. With low rainfall, drip irrigation is essential for growing Petunia successfully. Mulch heavily to conserve soil moisture.
Wasatch County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.6
Drainage
Well Drained
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 1.6" | 0" | ❄️ Dormant |
| May | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Jun | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Jul | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Aug | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Sep | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Oct | — | 1.4" | 0" | ❄️ Dormant |
| Nov | — | 1.2" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Wasatch County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Petunia Planting Timeline — Wasatch County, UT
Petunia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 24 | Mar 24 – Apr 7 |
| Transplant Outdoors | May 26 | May 26 – Jun 9 |
| Bloom | August 4 | Aug 4 – Nov 10 |
· 12" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 6a
📆 Growing Season
130 days in Wasatch County
Growing Tips for Wasatch County
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 Wasatch County, UT?
Wasatch County is in Zone 6a with an average last frost of May 19. Plan your Petunia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Wasatch County, UT?
Wasatch County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 19 and first fall frost is September 26.
Your Wasatch County Garden Planner — Free
A 22-page printable planner built for Wasatch County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.