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When to Plant Geraniums in Cameron County, TX

Cameron County, Texas Zone 10a June

Your June gardening checklist

Your Cameron County, Texas garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost February 4
Avg. first frost December 22
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Harvest geraniums as they ripen

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Coming up in July — start thinking about
  • 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.

Cameron County, Texas is in USDA Zone 10a. The average last spring frost is February 4 and the first fall frost is December 22, giving you a growing season of approximately 321 days.

At an elevation of 4,025 feet, Cameron County receives approximately 58.6 inches of rainfall annually with predominantly loam soil. Summer highs average 103°F, so Geraniums may need afternoon shade and extra watering during peak heat. 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
Cameron County, TX (Zone 10a) Year-round
321 days
Last Spring Frost February 4
321 growing days
First Fall Frost December 22
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Cameron County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (95 days to spare)
Start indoors: Nov 8 Transplant: Dec 6 🌸 Bloom: Feb 14 – Sep 12
Recommended (50%) ✓ Fits season (83 days to spare)
Start indoors: Nov 26 Transplant: Dec 24 🌸 Bloom: Mar 4 – Sep 30
Safe Start (90%) ✓ Fits season (60 days to spare)
Start indoors: Dec 24 Transplant: Jan 21 🌸 Bloom: Apr 1 – Oct 28

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 Cameron County

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

Soil pH

Your soil pH (6.7–7.8) is more alkaline than Geraniums prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Cameron 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
14"
Between Plants
16"
Between Rows

Succession Planting Geraniums

5
successive plantings in your 321-day season

Sow every 8 weeks. Last sowing by Sep 13 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 675 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 1.6" 0" ❄️ Dormant
Feb 4.3" 2.2" 2.1" 💧 Light watering
Mar 4.3" 3.1" 1.2" 💧 Light watering
Apr 4.3" 6.1" 0" ✅ Rainfall sufficient
May 4.3" 9.2" 0" ✅ Rainfall sufficient
Jun 4.3" 9.1" 0" ✅ Rainfall sufficient
Jul 4.3" 7.5" 0" ✅ Rainfall sufficient
Aug 4.3" 6.9" 0" ✅ Rainfall sufficient
Sep 4.3" 5.6" 0" ✅ Rainfall sufficient
Oct 4.3" 3.8" 0.5" 💧 Light watering
Nov 4.3" 2.1" 2.2" 🚿 Regular watering
Dec 4.3" 1.4" 2.9" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Cameron 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 ~2,316 GDD — county provides 8,774 GDD Excellent fit

Geraniums Planting Timeline — Cameron County, TX

Geraniums Planting Calendar

Activity When Date Range
Start Indoors November 26 Nov 26 – Dec 10
Transplant Outdoors December 24 Dec 24 – Jan 7
Bloom March 4 Mar 4 – Sep 30

Plant 0.1" deep · 14" apart · Rows 16" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 10a

📆 Growing Season

321 days in Cameron County

Growing Tips for Geraniums in Cameron County

Direct sow Geraniums outdoors after February 04 in Cameron County when soil has warmed and frost danger has passed.

With summer highs reaching 103°F in Cameron County, provide afternoon shade for Geraniums and water deeply in the morning.

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 Cameron County, TX?

Cameron County is in Zone 10a with an average last frost of February 4. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cameron County, TX?

Cameron County, Texas is in USDA Hardiness Zone 10a. The average last spring frost is February 4 and first fall frost is December 22.

🌱

Your Cameron County Garden Planner — Free

A 22-page printable planner built for Cameron County (Zone 10a). 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 Cameron 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.