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When to Plant Tarragon in Jones County, IA

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.

Jones County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 11, giving you a growing season of approximately 169 days.

At an elevation of 837 feet, Jones County receives approximately 31.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Tarragon during the growing season.

Jones County, IA (Zone 5a) Moderate season
169 days
Last Spring Frost April 25
169 growing days
First Fall Frost October 11

Jones County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Transplant: Apr 28 🍅 Harvest: Jun 30 – Sep 8
Recommended (50%) ✓ Fits season (29 days to spare)
Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12
Safe Start (90%) ✓ Fits season (22 days to spare)
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 29

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 Jones County

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

Soil pH

Your soil pH (5.7โ€“6.8) overlaps with Tarragon's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Tarragon.

Organic Matter

Organic matter is excellent (4.0%) โ€” Tarragon will thrive.

How to Plant Tarragon

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

Succession Planting Tarragon

3
successive plantings in your 169-day season

Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.

Plant Water Budget

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

Water stress score is 6/10 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€” 1.2" 0" โ„๏ธ Dormant
Feb โ€” 1.5" 0" โ„๏ธ Dormant
Mar โ€” 2" 0" โ„๏ธ Dormant
Apr 1.7" 2.9" 0" โœ… Rainfall sufficient
May 1.7" 3.4" 0" โœ… Rainfall sufficient
Jun 1.7" 4.5" 0" โœ… Rainfall sufficient
Jul 1.7" 3.7" 0" โœ… Rainfall sufficient
Aug 1.7" 3.2" 0" โœ… Rainfall sufficient
Sep 1.7" 2.6" 0" โœ… Rainfall sufficient
Oct 1.7" 2.3" 0" โœ… Rainfall sufficient
Nov โ€” 2.2" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Jones 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 ~1,088 GDD — county provides 2,450 GDD Excellent fit

Tarragon Planting Timeline โ€” Jones County, IA

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors May 2 May 2 โ€“ May 16
Harvest July 4 Jul 4 โ€“ Sep 12

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 Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

169 days in Jones County

Growing Tips for Tarragon in Jones County

Direct sow Tarragon outdoors after April 25 in Jones 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 Jones County, IA?

Jones County is in Zone 5a with an average last frost of April 25. Plan your Tarragon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jones County, IA?

Jones County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jones County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Jones County, IA. Local conditions may vary. Last updated: April 2026.