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When to Plant Comfrey in Cache County, UT

Cache County, Utah Zone 6a May

May in the garden — Cache County, Utah

May is a pivotal month for Cache County, Utah gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost June 11
Avg. first frost September 2
Soil temp (4") 42°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
To set up a strong June, finish these tasks
  • Transplants going out: comfrey

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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.

Cache County, Utah is in USDA Zone 6a. The average last spring frost is June 11 and the first fall frost is September 2, giving you a growing season of approximately 83 days.

At an elevation of 6,265 feet, Cache County receives approximately 15.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Comfrey to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Comfrey successfully. Mulch heavily to conserve soil moisture.

Cache County, UT (Zone 6a) Very short season
83 days
Last Spring Frost June 11
83 growing days
First Fall Frost September 2

Cache County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 22 🍅 Harvest: Jul 24 – Oct 2
Recommended (50%) ✗ May not fit
Transplant: Jun 18 🍅 Harvest: Aug 20 – Oct 29
Safe Start (90%) ✗ May not fit
Transplant: Jul 1 🍅 Harvest: Sep 2 – Nov 11

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 Cache County

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

Soil pH

Your soil pH (6.6–8.4) is more alkaline than Comfrey prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Comfrey.

How to Plant Comfrey

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 191 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1.1" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2" 0" ❄️ Dormant
Jun 4.3" 1.1" 3.2" 🚿 Regular watering
Jul 4.3" 1.3" 3" 🚿 Regular watering
Aug 4.3" 1.5" 2.8" 🚿 Regular watering
Sep 4.3" 1.3" 3" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Cache 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 ~975 GDD — county provides 1,079 GDD Good fit

Comfrey Planting Timeline — Cache County, UT

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors June 18 Jun 18 – Jul 2
Harvest August 20 Aug 20 – Oct 29

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July Transplant Outdoors
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

83 days in Cache County

Growing Tips for Comfrey in Cache County

Direct sow Comfrey outdoors after June 11 in Cache County when soil has warmed and frost danger has passed.

Your 83.0-day growing season in Cache County is tight for Comfrey (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

Cache County receives only 16" 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 →

Frequently Asked Questions

When should I plant Comfrey in Cache County, UT?

Cache County is in Zone 6a with an average last frost of June 11. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cache County, UT?

Cache County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is June 11 and first fall frost is September 2.

🌱

Your Cache County Garden Planner — Free

A 24-page printable planner built for Cache 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 Cache County, UT. 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.