When to Plant Begonias in Starr County, TX
Your July planting checklist for Starr County, Texas
July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Starr County, Texas.
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Harvest begonias as they ripen
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
To set up a strong August, finish these tasks
- First harvests: begonias
Wax begonias (Begonia × semperflorens) are the workhorse shade bedding plant of American horticulture, offering continuous bloom from transplant to hard frost. Bronze or green-leaved varieties perform well from deep shade to full sun (in northern zones) and tolerate summer humidity better than most cool- season flowers. A staple of mass plantings, containers, and window boxes.
Starr County, Texas is in USDA Zone 9b. The average last spring frost is February 3 and the first fall frost is December 16, giving you a growing season of approximately 316 days.
At an elevation of 2,451 feet, Starr County receives approximately 55.4 inches of rainfall annually with predominantly loam soil. Summer highs average 98°F, so Begonias may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Begonias root diseases.
Starr County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.5
Drainage
Well Drained
Begonias Planting Risk Windows
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 Starr County
How your county's soil matches Begonias's growing requirements.
Soil pH
Your soil pH (6.8–7.5) is more alkaline than Begonias prefers (5.5–6.5). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Starr County is excellent for Begonias — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.1%). Annual compost additions will help Begonias.
How to Plant Begonias
Succession Planting Begonias
Sow every 8 weeks. Last sowing by Sep 17 to harvest before frost.
Begonias Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Begonias
Begonias needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Begonias Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.6" | 0" | ❄️ Dormant |
| Feb | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Mar | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Apr | 4.3" | 6.6" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 7.6" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 6.4" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4" | 0.3" | 💧 Light watering |
| Nov | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Dec | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec in Starr County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Begonias 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.
Begonias Planting Timeline — Starr County, TX
Begonias Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | November 25 | Nov 25 – Dec 9 |
| Transplant Outdoors | January 6 | Jan 6 – Jan 20 |
| Bloom | March 17 | Mar 17 – Sep 29 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 9b
📆 Growing Season
316 days in Starr County
Growing Tips for Begonias in Starr County
Direct sow Begonias outdoors after February 03 in Starr County when soil has warmed and frost danger has passed.
With summer highs reaching 98°F in Starr County, provide afternoon shade for Begonias and water deeply in the morning.
General growing tips
Start seeds indoors 10–12 weeks before last frost — seed is dust-fine; surface-sow on moist mix under lights, do not cover. Bottom heat (70–75°F) speeds germination. Transplant after frost; begonias are not direct-sown in practice. Pinch seedlings once for branching. Keep soil evenly moist; avoid waterlogged conditions. Bronze-leaf types tolerate more sun; green- leaf types prefer shade to part-sun.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Begonias in Other Locations
Frequently Asked Questions
When should I plant Begonias in Starr County, TX?
Starr County is in Zone 9b with an average last frost of February 3. Plan your Begonias planting based on this frost date — see the calendar above for exact timing.
What planting zone is Starr County, TX?
Starr County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 3 and first fall frost is December 16.
Your Starr County Garden Planner — Free
A 22-page printable planner built for Starr County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.