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When to Plant Stevia in Parker County, TX

Parker County, Texas Zone 8a May

Your May gardening checklist

Welcome to May in Zone 8a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 18
Avg. first frost November 12
Soil temp (4") 57°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
  1. Sow stevia in trays indoors

    Your window is short. These crops want several weeks of indoor growth before they go outside.

June prep starts now
  • 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.

Parker County, Texas is in USDA Zone 8a. The average last spring frost is March 18 and the first fall frost is November 12, giving you a growing season of approximately 239 days.

At an elevation of 4,469 feet, Parker County receives approximately 60.6 inches of rainfall annually with predominantly clay soil. Summer highs average 89°F, providing good warmth for Stevia during the growing season. Clay soil retains moisture well for Stevia, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Stevia root diseases.

Parker County, TX (Zone 8a) Long season
239 days
Last Spring Frost March 18
239 growing days
First Fall Frost November 12
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Parker County Soil Profile

Soil Type

Clay

Soil pH

7.1-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (100 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 22 – Jul 31
Recommended (50%) ✓ Fits season (92 days to spare)
Start indoors: Jan 28 Transplant: Apr 1 🍅 Harvest: Jun 3 – Aug 12
Safe Start (90%) ✓ Fits season (89 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🍅 Harvest: Jun 28 – Sep 6

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 Parker County

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

Soil pH

Your soil pH (7.1–8.4) is more alkaline than Stevia prefers (6.5–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Your clay soil in Parker County is workable for Stevia. Add compost annually to improve structure.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Stevia.

How to Plant Stevia

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

Succession Planting Stevia

4
successive plantings in your 239-day season

Sow every 6.9 weeks. Last sowing by Aug 14 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.2" 3.5" 0" ✅ Rainfall sufficient
Apr 2.2" 5.7" 0" ✅ Rainfall sufficient
May 2.2" 9.5" 0" ✅ Rainfall sufficient
Jun 2.2" 9.5" 0" ✅ Rainfall sufficient
Jul 2.2" 8" 0" ✅ Rainfall sufficient
Aug 2.2" 7.3" 0" ✅ Rainfall sufficient
Sep 2.2" 5.8" 0" ✅ Rainfall sufficient
Oct 2.2" 3.8" 0" ✅ Rainfall sufficient
Nov 2.2" 2.3" 0" ✅ Rainfall sufficient
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Parker 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 ~1,256 GDD — county provides 4,003 GDD Excellent fit

Stevia Planting Timeline — Parker County, TX

Stevia Planting Calendar

Activity When Date Range
Start Indoors January 28 Jan 28 – Feb 11
Transplant Outdoors April 1 Apr 1 – Apr 15
Direct Sow March 25 Mar 25 – Apr 15
Harvest June 3 Jun 3 – Aug 12

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Direct Sow
April Transplant Outdoors Direct Sow
May
June Harvest
July Harvest
August Harvest
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: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

239 days in Parker County

Growing Tips for Stevia in Parker County

Direct sow Stevia outdoors after March 18 in Parker County when soil has warmed and frost danger has passed.

With Parker County's clay soil (38% clay), work in 3-4 inches of compost before planting Stevia. Avoid tilling when soil is wet to prevent compaction.

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

With 61" of annual rainfall in Parker County, ensure good drainage for Stevia — excess moisture can promote root rot and fungal diseases.

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 Parker County, TX?

Parker County is in Zone 8a with an average last frost of March 18. Plan your Stevia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Parker County, TX?

Parker County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 18 and first fall frost is November 12.

🌱

Your Parker County Garden Planner — Free

A 24-page printable planner built for Parker 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.

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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 Parker 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.