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When to Plant Tarragon in Otero County, CO

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.

Otero County, Colorado is in USDA Zone 6a. The average last spring frost is April 26 and the first fall frost is October 9, giving you a growing season of approximately 166 days.

At an elevation of 4,145 feet, Otero County receives approximately 14.2 inches of rainfall annually with predominantly loam soil. Summer highs average 90ยฐF, providing good warmth for Tarragon during the growing season. With low rainfall, drip irrigation is essential for growing Tarragon successfully. Mulch heavily to conserve soil moisture.

Otero County, CO (Zone 6a) Moderate season
166 days
Last Spring Frost April 26
166 growing days
First Fall Frost October 9

Otero County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Transplant: Apr 29 🍅 Harvest: Jul 1 – Sep 9
Recommended (50%) ✓ Fits season (26 days to spare)
Transplant: May 3 🍅 Harvest: Jul 5 – Sep 13
Safe Start (90%) ✓ Fits season (24 days to spare)
Transplant: May 20 🍅 Harvest: Jul 22 – Sep 30

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 Otero County

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

Soil pH

Your soil pH (6.4โ€“8.1) overlaps with Tarragon's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Otero County is excellent for Tarragon โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Tarragon.

How to Plant Tarragon

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

Succession Planting Tarragon

3
successive plantings in your 166-day season

Sow every 6.9 weeks. Last sowing by Jul 11 to harvest before frost.

Plant Water Budget

Plant needs
0.4″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 72 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” consider drought-tolerant varieties and mulching

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 โ€” 1" 0" โ„๏ธ Dormant
Feb โ€” 0.9" 0" โ„๏ธ Dormant
Mar โ€” 1.2" 0" โ„๏ธ Dormant
Apr 1.7" 1.4" 0.3" ๐Ÿ’ง Light watering
May 1.7" 1.5" 0.2" ๐Ÿ’ง Light watering
Jun 1.7" 1.1" 0.6" ๐Ÿ’ง Light watering
Jul 1.7" 1.5" 0.2" ๐Ÿ’ง Light watering
Aug 1.7" 1.3" 0.4" ๐Ÿ’ง Light watering
Sep 1.7" 1.1" 0.6" ๐Ÿ’ง Light watering
Oct 1.7" 1.2" 0.5" ๐Ÿ’ง Light watering
Nov โ€” 1" 0" โ„๏ธ Dormant
Dec โ€” 0.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Otero County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,312 GDD — county provides 2,905 GDD Excellent fit

Tarragon Planting Timeline โ€” Otero County, CO

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors May 3 May 3 โ€“ May 17
Harvest July 5 Jul 5 โ€“ Sep 13

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.4"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

166 days in Otero County

Growing Tips for Tarragon in Otero County

Direct sow Tarragon outdoors after April 26 in Otero 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 Otero County, CO?

Otero County is in Zone 6a with an average last frost of April 26. Plan your Tarragon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Otero County, CO?

Otero County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is April 26 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Otero County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Otero County, CO. Local conditions may vary. Last updated: April 2026.