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When to Plant Begonias in Frio County, TX

Frio County, Texas Zone 9a June

This month in Frio County, Texas

Welcome to June in Zone 9a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 26
Avg. first frost November 26
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. It's harvest week for begonias

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

Looking ahead to July
  • First harvests: begonias

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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.

Frio County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.

At an elevation of 3,892 feet, Frio County receives approximately 51 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Begonias during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Begonias root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Frio County, TX (Zone 9a) Year-round
273 days
Last Spring Frost February 26
273 growing days
First Fall Frost November 26

Frio County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.2

Drainage

Well Drained

Begonias Planting Risk Windows

Early Start (70% safe) ✓ Fits season (47 days to spare)
Start indoors: Dec 5 Transplant: Jan 23 🌸 Bloom: Apr 3 – Oct 2
Recommended (50%) ✓ Fits season (42 days to spare)
Start indoors: Dec 18 Transplant: Feb 5 🌸 Bloom: Apr 16 – Oct 15
Safe Start (90%) ✓ Fits season (35 days to spare)
Start indoors: Jan 10 Transplant: Feb 28 🌸 Bloom: May 9 – Nov 7

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 Frio County

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

Soil pH

Your soil pH (6.4–7.2) is more alkaline than Begonias prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Begonias.

Organic Matter

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

How to Plant Begonias

8"
Between Plants
10"
Between Rows

Succession Planting Begonias

4
successive plantings in your 273-day season

Sow every 8 weeks. Last sowing by Aug 28 to harvest before frost.

Begonias Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,264 gal / 100 sq ft

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 1.2" 0" ❄️ Dormant
Feb 4.3" 1.9" 2.4" 🚿 Regular watering
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 4.9" 0" ✅ Rainfall sufficient
May 4.3" 7.5" 0" ✅ Rainfall sufficient
Jun 4.3" 9.4" 0" ✅ Rainfall sufficient
Jul 4.3" 6.3" 0" ✅ Rainfall sufficient
Aug 4.3" 5.2" 0" ✅ Rainfall sufficient
Sep 4.3" 4.6" 0" ✅ Rainfall sufficient
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 4.3" 1.6" 2.7" 🚿 Regular watering
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Frio 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 needs ~1,580 GDD — county provides 5,411 GDD Excellent fit

Begonias Planting Timeline — Frio County, TX

Begonias Planting Calendar

Activity When Date Range
Start Indoors December 18 Dec 18 – Jan 1
Transplant Outdoors February 5 Feb 5 – Feb 19
Bloom April 16 Apr 16 – Oct 15

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors
March
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
November
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 9a

📆 Growing Season

273 days in Frio County

Growing Tips for Begonias in Frio County

Direct sow Begonias outdoors after February 26 in Frio County when soil has warmed and frost danger has passed.

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 →

Frequently Asked Questions

When should I plant Begonias in Frio County, TX?

Frio County is in Zone 9a with an average last frost of February 26. Plan your Begonias planting based on this frost date — see the calendar above for exact timing.

What planting zone is Frio County, TX?

Frio County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is November 26.

🌱

Your Frio County Garden Planner — Free

A 22-page printable planner built for Frio 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 Frio 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.