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When to Plant Petunia in Dimmit County, TX

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.

Dimmit County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is December 1, giving you a growing season of approximately 278 days.

At an elevation of 2,638 feet, Dimmit County receives approximately 63.2 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Petunia during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Petunia root diseases.

Annual Blooms in Summer Pollinator-friendly Fragrant
Dimmit County, TX (Zone 9a) Year-round
278 days
Last Spring Frost February 26
278 growing days
First Fall Frost December 1
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Dimmit County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

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 1.6" 0" ❄️ Dormant
Feb 4.3" 2" 2.3" 🚿 Regular watering
Mar 4.3" 4" 0.3" 💧 Light watering
Apr 4.3" 6.3" 0" ✅ Rainfall sufficient
May 4.3" 9.1" 0" ✅ Rainfall sufficient
Jun 4.3" 11.3" 0" ✅ Rainfall sufficient
Jul 4.3" 8.6" 0" ✅ Rainfall sufficient
Aug 4.3" 8.1" 0" ✅ Rainfall sufficient
Sep 4.3" 5.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 4.3" 1.4" 2.9" 🚿 Regular watering

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

Petunia Planting Timeline — Dimmit County, TX

Petunia Planting Calendar

Activity When Date Range
Start Indoors January 1 Jan 1 – Jan 15
Transplant Outdoors February 12 Feb 12 – Feb 26
Bloom April 23 Apr 23 – Sep 24

· 12" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors
March
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October
November
December
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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 9a

📆 Growing Season

278 days in Dimmit County

Growing Tips for Dimmit 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 →

Frequently Asked Questions

When should I plant Petunia in Dimmit County, TX?

Dimmit County is in Zone 9a with an average last frost of February 26. Plan your Petunia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dimmit County, TX?

Dimmit County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is December 1.

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Your Dimmit County Garden Planner — Free

A 22-page printable planner built for Dimmit County (Zone 9a). 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 Dimmit County, TX. 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.