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When to Plant Geraniums in Mills County, TX

Mills County, Texas Zone 8b June

June in the garden — Mills County, Texas

Welcome to June in Zone 8b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 23
Avg. first frost November 12
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 14 hrs
  1. Begin indoor sowing: geraniums

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Basket week: geraniums

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

To set up a strong July, finish these tasks
  • First harvests: geraniums

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Geraniums (Pelargonium × hortorum) are tender perennials grown as warm-season annuals throughout North America. Prized for their bold flower clusters, long bloom period, and tolerance of summer heat when planted in well-drained soil, they anchor window boxes, containers, and bed borders from late spring until hard frost. Zones 9b–11b can overwinter plants in the ground.

Mills County, Texas is in USDA Zone 8b. The average last spring frost is March 23 and the first fall frost is November 12, giving you a growing season of approximately 234 days.

At an elevation of 4,208 feet, Mills County receives approximately 61.7 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Geraniums during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Geraniums root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Mills County, TX (Zone 8b) Long season
234 days
Last Spring Frost March 23
234 growing days
First Fall Frost November 12
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Mills County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (27 days to spare)
Start indoors: Jan 1 Transplant: Feb 26 🌸 Bloom: May 7 – Oct 8
Recommended (50%) ✓ Fits season (24 days to spare)
Start indoors: Jan 12 Transplant: Mar 9 🌸 Bloom: May 18 – Oct 19
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Feb 3 Transplant: Mar 31 🌸 Bloom: Jun 9 – Nov 10

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 Mills County

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

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Geraniums prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Mills County is excellent for Geraniums — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Geraniums.

How to Plant Geraniums

0.1"
Planting Depth
12"
Between Plants
14"
Between Rows

Succession Planting Geraniums

3
successive plantings in your 234-day season

Sow every 8 weeks. Last sowing by Aug 04 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Geraniums

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

Month Geraniums Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 4.3" 3.8" 0.5" 💧 Light watering
Apr 4.3" 6.2" 0" ✅ Rainfall sufficient
May 4.3" 10.5" 0" ✅ Rainfall sufficient
Jun 4.3" 9.5" 0" ✅ Rainfall sufficient
Jul 4.3" 7.5" 0" ✅ Rainfall sufficient
Aug 4.3" 7" 0" ✅ Rainfall sufficient
Sep 4.3" 5.6" 0" ✅ Rainfall sufficient
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 1.4" 0" ❄️ Dormant

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

Geraniums 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.

Geraniums needs ~1,488 GDD — county provides 4,095 GDD Excellent fit

Geraniums Planting Timeline — Mills County, TX

Geraniums Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 – Jan 26
Transplant Outdoors March 9 Mar 9 – Mar 23
Bloom May 18 May 18 – Oct 19

Plant 0.1" deep · 12" apart · Rows 14" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

234 days in Mills County

Growing Tips for Geraniums in Mills County

Direct sow Geraniums outdoors after March 23 in Mills County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 10–12 weeks before last frost — germination is slow and erratic without bottom heat (70–75°F). Transplant after frost danger passes. Geraniums rarely direct-sown; cuttings or transplants are the standard. Deadhead spent umbels weekly to maintain continuous bloom. Let soil dry slightly between waterings to prevent root rot. In zones 10–11 plants may be left in ground year-round or overwintered as houseplants.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Geraniums in Mills County, TX?

Mills County is in Zone 8b with an average last frost of March 23. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mills County, TX?

Mills County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 23 and first fall frost is November 12.

🌱

Your Mills County Garden Planner — Free

A 22-page printable planner built for Mills County (Zone 8b). 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 Mills 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.