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When to Plant Zinnia in Dimmit County, TX

Zinnia (Zinnia elegans) is a fast-growing, heat-loving annual that produces bold, dahlia-like blooms from early summer until hard frost. One of the easiest flowers to grow from direct-sown seed, zinnias thrive in hot, dry conditions and are magnets for butterflies and beneficial insects. They make excellent companion plants alongside marigolds in the vegetable garden.

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 Zinnia during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Zinnia root diseases.

Annual Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Dimmit County, TX (Zone 9a) Year-round
278 days
Last Spring Frost February 26
278 growing days
First Fall Frost December 1

Dimmit County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Monthly Watering Guide for Zinnia

Zinnia needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Zinnia 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.

Zinnia Planting Timeline — Dimmit County, TX

Zinnia Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors February 5 Feb 5 – Feb 19
Direct Sow February 5 Feb 5 – Feb 26
Bloom April 16 Apr 16 – Oct 1

Plant 0.3" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 9a

📆 Growing Season

278 days in Dimmit County

Growing Tips for Dimmit County

Direct-sow after last frost when soil reaches 60°F; seeds germinate in 5-7 days. In zones 3-5 a brief indoor start (4 weeks) is worthwhile but transplant carefully — zinnias dislike root disturbance. Deadhead frequently to extend bloom. Excellent cut flower; harvesting regularly encourages branching. Avoid overhead watering to reduce powdery mildew.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zinnia in Dimmit County, TX?

Dimmit County is in Zone 9a with an average last frost of February 26. Plan your Zinnia 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.

🌱

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: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.