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When to plant Comfrey in Granite County, MT

Granite County's 114-day season only supports one Comfrey planting per year. Sow between June 5 and June 19 for the best chance at full maturity before September 20.

When to Plant Comfrey in Granite County, MT

Granite County, Montana Zone 5a June

June to-do list for Granite County, Montana

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Granite County, Montana.

Avg. last frost May 29
Avg. first frost September 20
Soil temp (4") 44°F
Watering High
Pest pressure High
Daylight 15.6 hrs
  1. Move comfrey into the garden

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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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.

Granite County, Montana is in USDA Zone 5a. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 7,177 feet, Granite County receives approximately 18.9 inches of rainfall annually with predominantly loam soil. Summer highs average 81°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.

Granite County, MT (Zone 5a) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20

Granite County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.6

Drainage

Well Drained

Comfrey Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 25 🍅 Harvest: Jul 27 – Oct 5
Recommended (50%) ✗ May not fit
Transplant: Jun 5 🍅 Harvest: Aug 7 – Oct 16
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 Granite County

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

Soil pH

Your soil pH (6.6–7.6) is more alkaline than Comfrey prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Comfrey.

How to Plant Comfrey

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

Succession Planting Comfrey

2
successive plantings in your 114-day season

Sow every 6.9 weeks. Last sowing by Jun 22 to harvest before frost.

Comfrey Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 370 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.5" 2.8" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Granite 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 ~806 GDD — county provides 1,225 GDD Excellent fit

Comfrey Planting Timeline — Granite County, MT

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors June 5 Jun 5 – Jun 19
Harvest August 7 Aug 7 – Oct 16

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 5a

📆 Growing Season

114 days in Granite County

Growing Tips for Comfrey in Granite County

Direct sow Comfrey outdoors after May 29 in Granite County when soil has warmed and frost danger has passed.

Granite 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 →

Frequently Asked Questions

When should I plant Comfrey in Granite County, MT?

Granite County is in Zone 5a with an average last frost of May 29. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Granite County, MT?

Granite County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 29 and first fall frost is September 20.

When should I plant Comfrey in Granite County, MT?

In Granite County, MT, plant Comfrey after the last frost (around May 29) and before the first frost (around September 20). Best results when soil holds above 50°F.

What growing zone is Granite County, MT for Comfrey?

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

Can Comfrey grow in Granite County's climate?

Yes — Comfrey grows well in Granite County's temperate climate. Granite County averages a 114-day frost-free season, with last frost around May 29 and first frost around September 20.

🌱

Your Granite County Garden Planner — Free

A 22-page printable planner built for Granite County (Zone 5a). 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 Granite County, MT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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