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When to Plant Tarragon in Knox County, TX

Knox County, Texas Zone 8a May

This month in Knox County, Texas

Your garden in Knox County, Texas is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 24
Avg. first frost November 12
Soil temp (4") 64°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
Coming up in June — start thinking about
  • First harvests: tarragon

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French tarragon is a perennial herb with slender leaves and a distinctive anise-like flavor essential in French cooking. It does not produce viable seed and must be propagated vegetatively.

Knox County, Texas is in USDA Zone 8a. The average last spring frost is March 24 and the first fall frost is November 12, giving you a growing season of approximately 233 days.

At an elevation of 1,847 feet, Knox County receives approximately 51.2 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Tarragon during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Tarragon root diseases.

Knox County, TX (Zone 8a) Long season
233 days
Last Spring Frost March 24
233 growing days
First Fall Frost November 12

Knox 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 (90 days to spare)
Transplant: Mar 24 🍅 Harvest: May 26 – Aug 4
Recommended (50%) ✓ Fits season (93 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 2 – Aug 11
Safe Start (90%) ✓ Fits season (86 days to spare)
Transplant: Apr 20 🍅 Harvest: Jun 22 – Aug 31

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 Knox County

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

Soil pH

Your soil pH (6.4–7.2) is within Tarragon's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Tarragon.

How to Plant Tarragon

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

Succession Planting Tarragon

4
successive plantings in your 233-day season

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

Plant Water Budget

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

Monthly Watering Guide for Tarragon

Tarragon needs approximately 0.4 inches of water per week (1.7" per month). Here's how your county's rainfall compares month by month.

Month Tarragon Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 1.7" 3.2" 0" ✅ Rainfall sufficient
Apr 1.7" 6.4" 0" ✅ Rainfall sufficient
May 1.7" 6.7" 0" ✅ Rainfall sufficient
Jun 1.7" 7.3" 0" ✅ Rainfall sufficient
Jul 1.7" 6.5" 0" ✅ Rainfall sufficient
Aug 1.7" 5.9" 0" ✅ Rainfall sufficient
Sep 1.7" 5.4" 0" ✅ Rainfall sufficient
Oct 1.7" 3.3" 0" ✅ Rainfall sufficient
Nov 1.7" 1.8" 0" ✅ Rainfall sufficient
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Knox County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Tarragon 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.

Tarragon needs ~1,481 GDD — county provides 4,601 GDD Excellent fit

Tarragon Planting Timeline — Knox County, TX

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors March 31 Mar 31 – Apr 14
Harvest June 2 Jun 2 – Aug 11

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

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April Transplant Outdoors
May
June Harvest
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.4"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 8a

📆 Growing Season

233 days in Knox County

Growing Tips for Tarragon in Knox County

Direct sow Tarragon outdoors after March 24 in Knox County when soil has warmed and frost danger has passed.

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

General growing tips

Purchase plants or divisions as French tarragon does not grow true from seed. Plant in well-drained soil. Divide every 3-4 years to maintain vigor. Harvest tips regularly for best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Tarragon in Knox County, TX?

Knox County is in Zone 8a with an average last frost of March 24. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Knox County, TX?

Knox County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 24 and first fall frost is November 12.

🌱

Your Knox County Garden Planner — Free

A 24-page printable planner built for Knox 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 Knox 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.