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When to Plant Tarragon in Lassen County, CA

Lassen County, California Zone 7a May

What to do in May

Here's what deserves your attention in Lassen County, California this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost May 28
Avg. first frost September 29
Soil temp (4") 58°F
Watering Critical
Pest pressure Low
Daylight 14.3 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: 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.

Lassen County, California is in USDA Zone 7a. The average last spring frost is May 28 and the first fall frost is September 29, giving you a growing season of approximately 124 days.

At an elevation of 1,854 feet, Lassen County receives approximately 43.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Tarragon to ensure they mature before fall.

Lassen County, CA (Zone 7a) Short season
124 days
Last Spring Frost May 28
124 growing days
First Fall Frost September 29
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Lassen County Soil Profile

Soil Type

Loam

Soil pH

6.1-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 25 🍅 Harvest: Jul 27 – Oct 5
Recommended (50%) ✗ May not fit
Transplant: Jun 4 🍅 Harvest: Aug 6 – Oct 15
Safe Start (90%) ✗ May not fit
Transplant: Jun 26 🍅 Harvest: Aug 28 – Nov 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 Lassen County

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

Soil pH

Your soil pH (6.1–7.5) is within Tarragon's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Tarragon.

How to Plant Tarragon

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

Succession Planting Tarragon

2
successive plantings in your 124-day season

Sow every 6.9 weeks. Last sowing by Jul 01 to harvest before frost.

Plant Water Budget

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

Water stress score is 6/10 — 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 9.2" 0" ❄️ Dormant
Feb 9.8" 0" ❄️ Dormant
Mar 7.7" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 1.7" 1" 0.7" 💧 Light watering
Jun 1.7" 0.2" 1.5" 🚿 Regular watering
Jul 1.7" 0" 1.7" 🚿 Regular watering
Aug 1.7" 0" 1.7" 🚿 Regular watering
Sep 1.7" 0.5" 1.2" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 3.9" 0" ❄️ Dormant
Dec 6.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Lassen 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 ~975 GDD — county provides 1,612 GDD Excellent fit

Tarragon Planting Timeline — Lassen County, CA

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors June 4 Jun 4 – Jun 18
Harvest August 6 Aug 6 – Oct 15

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July
August Harvest
September Harvest
October Harvest
November
December
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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 7a

📆 Growing Season

124 days in Lassen County

Growing Tips for Tarragon in Lassen County

Direct sow Tarragon outdoors after May 28 in Lassen 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 Lassen County, CA?

Lassen County is in Zone 7a with an average last frost of May 28. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lassen County, CA?

Lassen County, California is in USDA Hardiness Zone 7a. The average last spring frost is May 28 and first fall frost is September 29.

🌱

Your Lassen County Garden Planner — Free

A 24-page printable planner built for Lassen County (Zone 7a). 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 Lassen County, CA. 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.