When to Plant Geraniums in Callahan County, TX
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.
Callahan County, Texas is in USDA Zone 8a. The average last spring frost is March 21 and the first fall frost is November 16, giving you a growing season of approximately 240 days.
At an elevation of 4,241 feet, Callahan County receives approximately 59.1 inches of rainfall annually with predominantly loam soil. Summer highs average 91°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.
Callahan County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.4
Drainage
Well Drained
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 | — | 1.9" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.3" | 1" | 💧 Light watering |
| Apr | 4.3" | 5.9" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 7.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 11" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 8.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 6.1" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 5.7" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Nov | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Callahan County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Geraniums Planting Timeline — Callahan County, TX
Geraniums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 10 | Jan 10 – Jan 24 |
| Transplant Outdoors | March 14 | Mar 14 – Mar 28 |
| Bloom | May 23 | May 23 – Oct 10 |
Plant 0.1" deep · 12" apart · Rows 14" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors |
| April | — |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 8a
📆 Growing Season
240 days in Callahan County
Growing Tips for Callahan County
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 →
Geraniums in Other Locations
Frequently Asked Questions
When should I plant Geraniums in Callahan County, TX?
Callahan County is in Zone 8a with an average last frost of March 21. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.
What planting zone is Callahan County, TX?
Callahan County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 21 and first fall frost is November 16.
Your Callahan County Garden Planner — Free
A 22-page printable planner built for Callahan County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.