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When to plant Chervil in Cascade County, MT

In Cascade County, plant Chervil in spring between May 12 and June 2, once soil temps hold above 50°F. Cascade County's last frost averages May 19, so be cautious and check the 10-day forecast before planting tender crops. For a fall crop, sow between June 29 and July 13 — roughly 40–60 days before the first frost on September 21.

When to Plant Chervil in Cascade County, MT

Cascade County, Montana Zone 4b June

Your June game plan for Cascade County, Montana

Welcome to June in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 19
Avg. first frost September 21
Soil temp (4") 44°F
Watering High
Pest pressure High
Daylight 15.7 hrs
  1. Start chervil indoors

    Label every cell. You will absolutely forget which is which otherwise.

  2. Basket week: chervil

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

  3. Kick off the fall garden with chervil

    Count back from your first frost (September 21) — these need to mature before the cold arrives.

Get ahead of July
  • First harvests: chervil

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Chervil is a delicate herb with a subtle anise-parsley flavor, essential in French cuisine as part of fines herbes. It prefers cool conditions and partial shade.

Cascade County, Montana is in USDA Zone 4b. The average last spring frost is May 19 and the first fall frost is September 21, giving you a growing season of approximately 125 days.

At an elevation of 6,585 feet, Cascade County receives approximately 21.8 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Chervil to ensure they mature before fall.

Cascade County, MT (Zone 4b) Short season
125 days
Last Spring Frost May 19
125 growing days
First Fall Frost September 21

Cascade County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.2

Drainage

Well Drained

Chervil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Mar 31 Transplant: May 5 🍅 Harvest: Jun 16 – Aug 18
Recommended (50%) ✓ Fits season (27 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jun 23 – Aug 25
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: May 1 Transplant: Jun 5 🍅 Harvest: Jul 17 – Sep 18

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 Cascade County

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

Soil pH

Your soil pH (6.8–8.2) is more alkaline than Chervil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Chervil.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Chervil.

How to Plant Chervil

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Chervil

3
successive plantings in your 125-day season

Sow every 4.6 weeks. Last sowing by Jul 23 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

Chervil Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/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 Chervil

Chervil needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Chervil Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.5" 0.7" 💧 Light watering
Jul 2.2" 2.1" 0.1" 💧 Light watering
Aug 2.2" 2" 0.2" 💧 Light watering
Sep 2.2" 1.8" 0.4" 💧 Light watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Chervil 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.

Chervil needs ~612 GDD — county provides 1,531 GDD Excellent fit

Chervil Planting Timeline — Cascade County, MT

Chervil Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 – Apr 21
Transplant Outdoors May 12 May 12 – May 26
Direct Sow May 12 May 12 – Jun 2
Harvest June 23 Jun 23 – Aug 25
Fall Sowing June 29 Jun 29 – Jul 13

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Direct Sow Fall Sowing Harvest
July Fall Sowing Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

125 days in Cascade County

Growing Tips for Chervil in Cascade County

Direct sow Chervil outdoors after May 19 in Cascade County when soil has warmed and frost danger has passed.

Common pests for Chervil in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in early spring or fall as chervil bolts in heat. Provide shade and cool conditions. Harvest outer leaves as needed; use fresh as it loses flavor when dried.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chervil in Cascade County, MT?

Cascade County is in Zone 4b with an average last frost of May 19. Plan your Chervil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cascade County, MT?

Cascade County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 19 and first fall frost is September 21.

When should I plant Chervil in Cascade County, MT?

In Cascade County, MT, plant Chervil after the last frost (around May 19) and before the first frost (around September 21). Best results when soil holds above 50°F.

What growing zone is Cascade County, MT for Chervil?

Cascade County sits in USDA Zone 4b. Chervil grows reliably in zones 3a through 10b, so it's a good fit here.

Can Chervil grow in Cascade County's climate?

Yes — Chervil grows well in Cascade County's temperate climate. Cascade County averages a 125-day frost-free season, with last frost around May 19 and first frost around September 21.

🌱

Your Cascade County Garden Planner — Free

A 22-page printable planner built for Cascade County (Zone 4b). 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 Cascade County, MT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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