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When to Plant Chervil in La Plata County, CO

La Plata County, Colorado Zone 6a May

La Plata County, Colorado gardeners: here's your May plan

Each item below is timed to La Plata County, Colorado's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 31
Avg. first frost September 21
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14 hrs
  1. Harden off and plant chervil

    Frost risk is low now in La Plata County, Colorado. If you've been covering beds overnight, you can stop.

  2. Sow chervil where they'll grow

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

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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.

La Plata County, Colorado is in USDA Zone 6a. The average last spring frost is May 31 and the first fall frost is September 21, giving you a growing season of approximately 113 days.

At an elevation of 5,246 feet, La Plata County receives approximately 14.9 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. With low rainfall, drip irrigation is essential for growing Chervil successfully. Mulch heavily to conserve soil moisture.

La Plata County, CO (Zone 6a) Short season
113 days
Last Spring Frost May 31
113 growing days
First Fall Frost September 21
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La Plata County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (21 days to spare)
Start indoors: Apr 9 Transplant: May 7 🍅 Harvest: Jun 18 – Aug 20
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Apr 26 Transplant: May 24 🍅 Harvest: Jul 5 – Sep 6
Safe Start (90%) ✓ Fits season (10 days to spare)
Start indoors: May 22 Transplant: Jun 19 🍅 Harvest: Jul 31 – Oct 2

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 La Plata County

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

Soil pH

Your soil pH (6.2–7.9) is more alkaline than Chervil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

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 10 weeks before your first frost date for a fall harvest.

Succession Planting Chervil

3
successive plantings in your 113-day season

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

For a dedicated fall crop, sow by Jul 13.

Plant Water Budget

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

Water stress score is 8/10 — 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 0.9" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 2.2" 1.6" 0.6" 💧 Light watering
Jun 2.2" 0.9" 1.3" 🚿 Regular watering
Jul 2.2" 1.4" 0.8" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
Oct 1.5" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in La Plata 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 1,384 GDD Excellent fit

Chervil Planting Timeline — La Plata County, CO

Chervil Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 – May 10
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest July 5 Jul 5 – Sep 6
Fall Sowing July 13 Jul 13 – Jul 27

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Fall Sowing Harvest
August Harvest
September Harvest
October
November
December
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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 6a

📆 Growing Season

113 days in La Plata County

Growing Tips for Chervil in La Plata County

Direct sow Chervil outdoors after May 31 in La Plata 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 La Plata County, CO?

La Plata County is in Zone 6a with an average last frost of May 31. Plan your Chervil planting based on this frost date — see the calendar above for exact timing.

What planting zone is La Plata County, CO?

La Plata County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 31 and first fall frost is September 21.

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Your La Plata County Garden Planner — Free

A 24-page printable planner built for La Plata County (Zone 6a). 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 La Plata County, CO. 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.