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When to plant Comfrey in Rangely, CO

In Rangely, Comfrey is a spring-only crop. Plant June 9–June 23 once soil hits 50°F.

When to Plant Comfrey in Rangely, CO

Rio Blanco County, Colorado Zone 5b June

June in Rio Blanco County, Colorado — your action list

We've pulled the most time-sensitive tasks for Rio Blanco County, Colorado this June and put them front and centre. Tackle them in order.

Avg. last frost June 2
Avg. first frost September 17
Soil temp (4") 48°F
Watering High
Pest pressure High
Daylight 14.8 hrs
  1. Time to transplant comfrey

    Your last frost (June 2) has passed. These warm-season crops can handle outdoor soil now.

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Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.

Rangely, 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 Comfrey during the growing season. With low rainfall, drip irrigation is essential for growing Comfrey successfully. Mulch heavily to conserve soil moisture.

Rangely, CO (Zone 5b) Short season
107 days
Last Spring Frost June 2
107 growing days
First Fall Frost September 17

Rangely Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Comfrey Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 26 🍅 Harvest: Jul 28 – Oct 6
Recommended (50%) ✗ May not fit
Transplant: Jun 9 🍅 Harvest: Aug 11 – Oct 20
Safe Start (90%) ✗ May not fit
Transplant: Jun 27 🍅 Harvest: Aug 29 – Nov 7

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 Rangely

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

Soil pH

Your soil pH (6.4–7.7) is more alkaline than Comfrey 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 Comfrey — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Comfrey.

How to Plant Comfrey

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

Comfrey Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 290 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Comfrey

Comfrey needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Comfrey 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 4.3" 1.3" 3" 🚿 Regular watering
Jul 4.3" 1.4" 2.9" 🚿 Regular watering
Aug 4.3" 1.9" 2.4" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular 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.

Comfrey 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.

Comfrey needs ~1,088 GDD — county provides 1,551 GDD Excellent fit

Comfrey Planting Timeline — Rangely, CO

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors June 9 Jun 9 – Jun 23
Harvest August 11 Aug 11 – Oct 20

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–90 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 Comfrey in Rangely

Direct sow Comfrey outdoors after June 02 in Rio Blanco County when soil has warmed and frost danger has passed.

Rio Blanco County receives only 19" of rain annually. Comfrey needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant root cuttings 2 inches deep. Choose Bocking 14 variety to prevent self-seeding. Cut leaves 3-4 times per season for mulch or compost. Avoid planting near pathways as it spreads.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

When should I plant Comfrey in Rangely, CO?

In Rangely, CO, plant Comfrey 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 Rangely, CO for Comfrey?

Rangely sits in USDA Zone 5b. Comfrey grows reliably in zones 3a through 9b, so it's a good fit here.

Can Comfrey grow in Rangely's climate?

Yes — Comfrey grows well in Rangely's temperate climate. Rangely 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.

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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 Rio Blanco County, CO. Local conditions may vary. Last updated: June 2026.