When to plant Chervil in Rio Blanco County, CO
Spring Chervil in Rio Blanco County goes in May 19–June 9, once nighttime temps stop dipping near freezing. A second sowing from July 9 to July 23 extends the harvest into fall.
When to Plant Chervil in Rio Blanco County, CO
Your June planting checklist for Rio Blanco County, Colorado
Welcome to June in Zone 5b. These are the moves that will have the biggest impact on your growing season.
Looking ahead to July
- Starting indoors: chervil
- First harvests: chervil
- Fall sowing: chervil
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.
Rio Blanco County, Colorado is in USDA Zone 5b. The average last spring frost is June 2 and the first fall frost is September 17, giving you a growing season of approximately 107 days.
At an elevation of 6,974 feet, Rio Blanco County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Chervil during the growing season. With low rainfall, drip irrigation is essential for growing Chervil successfully. Mulch heavily to conserve soil moisture.
Rio Blanco County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.7
Drainage
Well Drained
Chervil 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 Rio Blanco County
How your county's soil matches Chervil's growing requirements.
Soil pH
Your soil pH (6.4–7.7) is more alkaline than Chervil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Rio Blanco County is excellent for Chervil — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Chervil.
How to Plant Chervil
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Chervil
Sow every 4.6 weeks. Last sowing by Jul 19 to harvest before frost.
For a dedicated fall crop, sow by Jul 09.
Chervil Water Budget
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | — | 2.1" | 0" | ❄️ Dormant |
| Jun | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| Jul | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Aug | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Sep | 2.2" | 1.6" | 0.6" | 💧 Light watering |
| Oct | — | 1.6" | 0" | ❄️ Dormant |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Rio Blanco 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 — Rio Blanco County, CO
Chervil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 28 | Apr 28 – May 12 |
| Transplant Outdoors | May 26 | May 26 – Jun 9 |
| Direct Sow | May 19 | May 19 – Jun 9 |
| Harvest | July 7 | Jul 7 – Sep 8 |
| Fall Sowing | July 9 | Jul 9 – Jul 23 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 | — |
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 5b
📆 Growing Season
107 days in Rio Blanco County
Growing Tips for Chervil in Rio Blanco County
Direct sow Chervil outdoors after June 02 in Rio Blanco 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 Rio Blanco County, CO?
Rio Blanco County is in Zone 5b with an average last frost of June 2. Plan your Chervil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Rio Blanco County, CO?
Rio Blanco County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 2 and first fall frost is September 17.
When should I plant Chervil in Rio Blanco County, CO?
In Rio Blanco County, CO, plant Chervil after the last frost (around June 2) and before the first frost (around September 17). Best results when soil holds above 50°F.
What growing zone is Rio Blanco County, CO for Chervil?
Rio Blanco County sits in USDA Zone 5b. Chervil grows reliably in zones 3a through 10b, so it's a good fit here.
Can Chervil grow in Rio Blanco County's climate?
Yes — Chervil grows well in Rio Blanco County's temperate climate. Rio Blanco County averages a 107-day frost-free season, with last frost around June 2 and first frost around September 17.
Your Rio Blanco County Garden Planner — Free
A 22-page printable planner built for Rio Blanco County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.