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When to Plant Stevia in Frio County, TX

Frio County, Texas Zone 9a May

What to do in May

Here's what deserves your attention in Frio County, Texas this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost February 26
Avg. first frost November 26
Soil temp (4") 63°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Start harvesting stevia

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

June will be here before you know it — start on
  • First harvests: stevia

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Stevia is a subtropical herb whose leaves contain natural sweeteners 200-300 times sweeter than sugar. It is grown as an annual in most climates.

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 Stevia during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Stevia root diseases.

Frio County, TX (Zone 9a) Year-round
273 days
Last Spring Frost February 26
273 growing days
First Fall Frost November 26
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Frio County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (138 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: Apr 24 – Jul 3
Recommended (50%) ✓ Fits season (133 days to spare)
Start indoors: Jan 15 Transplant: Mar 5 🍅 Harvest: May 7 – Jul 16
Safe Start (90%) ✓ Fits season (126 days to spare)
Start indoors: Feb 7 Transplant: Mar 28 🍅 Harvest: May 30 – Aug 8

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 Stevia's growing requirements.

Soil pH

Your soil pH (6.4–7.2) overlaps with Stevia's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Stevia.

Organic Matter

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

How to Plant Stevia

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Stevia

5
successive plantings in your 273-day season

Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Stevia

Stevia needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Stevia Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 2.2" 1.9" 0.3" 💧 Light watering
Mar 2.2" 3.6" 0" ✅ Rainfall sufficient
Apr 2.2" 4.9" 0" ✅ Rainfall sufficient
May 2.2" 7.5" 0" ✅ Rainfall sufficient
Jun 2.2" 9.4" 0" ✅ Rainfall sufficient
Jul 2.2" 6.3" 0" ✅ Rainfall sufficient
Aug 2.2" 5.2" 0" ✅ Rainfall sufficient
Sep 2.2" 4.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.4" 0" ✅ Rainfall sufficient
Nov 2.2" 1.6" 0.6" 💧 Light 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.

Stevia 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.

Stevia needs ~1,481 GDD — county provides 5,411 GDD Excellent fit

Stevia Planting Timeline — Frio County, TX

Stevia Planting Calendar

Activity When Date Range
Start Indoors January 15 Jan 15 – Jan 29
Transplant Outdoors March 5 Mar 5 – Mar 19
Direct Sow March 5 Mar 5 – Mar 26
Harvest May 7 May 7 – Jul 16

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

273 days in Frio County

Growing Tips for Stevia in Frio County

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

Common pests for Stevia in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors under lights or buy transplants. Pinch flowers to encourage leaf production. Harvest leaves before flowering for maximum sweetness. Dry leaves for year-round use.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Stevia in Frio County, TX?

Frio County is in Zone 9a with an average last frost of February 26. Plan your Stevia 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 24-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: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.