When to Plant Chervil in Routt County, CO
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.
Routt County, Colorado is in USDA Zone 4a. The average last spring frost is June 12 and the first fall frost is September 8, giving you a growing season of approximately 88 days.
At an elevation of 5,381 feet, Routt County receives approximately 24.5 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.
Routt County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.9
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 Routt County
How your county's soil matches Chervil's growing requirements.
Soil pH
Your soil pH (6.7–7.9) is more alkaline than Chervil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Routt County is excellent for Chervil — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Chervil.
How to Plant Chervil
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Chervil
Sow every 4.6 weeks. Last sowing by Jul 10 to harvest before frost.
For a dedicated fall crop, sow by Jun 16.
Plant Water Budget
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 | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | — | 2.7" | 0" | ❄️ Dormant |
| May | — | 2.8" | 0" | ❄️ Dormant |
| Jun | 2.2" | 1.5" | 0.7" | 💧 Light watering |
| Jul | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Oct | — | 1.9" | 0" | ❄️ Dormant |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Routt 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 Planting Timeline — Routt County, CO
Chervil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 1 | May 1 – May 15 |
| Transplant Outdoors | June 5 | Jun 5 – Jun 19 |
| Direct Sow | June 5 | Jun 5 – Jun 26 |
| Harvest | July 17 | Jul 17 – Sep 18 |
| Fall Sowing | June 16 | Jun 16 – Jun 30 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow Fall Sowing |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| 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 4a
📆 Growing Season
88 days in Routt County
Growing Tips for Chervil in Routt County
Direct sow Chervil outdoors after June 12 in Routt 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 →
Chervil in Other Locations
Frequently Asked Questions
When should I plant Chervil in Routt County, CO?
Routt County is in Zone 4a with an average last frost of June 12. Plan your Chervil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Routt County, CO?
Routt County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 12 and first fall frost is September 8.
Plan Your Garden with Confidence
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