When to Plant Tarragon in Cassia County, ID
May in the garden — Cassia County, Idaho
May is a pivotal month for Cassia County, Idaho gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Transplant tarragon outside
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
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.
Cassia County, Idaho is in USDA Zone 6b. The average last spring frost is May 15 and the first fall frost is October 1, giving you a growing season of approximately 139 days.
At an elevation of 8,089 feet, Cassia County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, 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.
Cassia County Soil Profile
Soil Type
Loam
Soil pH
6.3-8.2
Drainage
Well Drained
Plant Planting Risk Windows
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 Cassia County
How your county's soil matches Tarragon's growing requirements.
Soil pH
Your soil pH (6.3–8.2) overlaps with Tarragon's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Cassia County is excellent for Tarragon — 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
Succession Planting Tarragon
Sow every 6.9 weeks. Last sowing by Jul 03 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — 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 | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.7" | 0" | ❄️ Dormant |
| Apr | — | 1.8" | 0" | ❄️ Dormant |
| May | 1.7" | 2.3" | 0" | ✅ Rainfall sufficient |
| Jun | 1.7" | 1.1" | 0.6" | 💧 Light watering |
| Jul | 1.7" | 1.5" | 0.2" | 💧 Light watering |
| Aug | 1.7" | 1.7" | 0" | ✅ Rainfall sufficient |
| Sep | 1.7" | 1.3" | 0.4" | 💧 Light watering |
| Oct | 1.7" | 1.6" | 0.1" | 💧 Light watering |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Cassia 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 Planting Timeline — Cassia County, ID
Tarragon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 22 | May 22 – Jun 5 |
| Harvest | July 24 | Jul 24 – Oct 2 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| 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: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
139 days in Cassia County
Growing Tips for Tarragon in Cassia County
Direct sow Tarragon outdoors after May 15 in Cassia 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 →
Tarragon in Other Locations
Frequently Asked Questions
When should I plant Tarragon in Cassia County, ID?
Cassia County is in Zone 6b with an average last frost of May 15. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cassia County, ID?
Cassia County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 15 and first fall frost is October 1.
Your Cassia County Garden Planner — Free
A 24-page printable planner built for Cassia County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.