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When to Plant Comfrey in Bear Lake County, ID

Bear Lake County, Idaho Zone 5a May

Your May gardening checklist

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

Avg. last frost May 24
Avg. first frost September 24
Soil temp (4") 42°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Plant out comfrey

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

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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.

Bear Lake County, Idaho is in USDA Zone 5a. The average last spring frost is May 24 and the first fall frost is September 24, giving you a growing season of approximately 123 days.

At an elevation of 5,220 feet, Bear Lake County receives approximately 18.6 inches of rainfall annually with predominantly loam soil. Summer highs average 83°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.

Bear Lake County, ID (Zone 5a) Short season
123 days
Last Spring Frost May 24
123 growing days
First Fall Frost September 24
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Bear Lake County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 13 🍅 Harvest: Jul 15 – Sep 23
Recommended (50%) ✗ May not fit
Transplant: May 31 🍅 Harvest: Aug 2 – Oct 11
Safe Start (90%) ✗ May not fit
Transplant: Jun 29 🍅 Harvest: Aug 31 – Nov 9

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 Bear Lake County

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

Soil pH

Your soil pH (6.7–8.2) is more alkaline than Comfrey prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Bear Lake 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 123-day season

Sow every 6.9 weeks. Last sowing by Jun 26 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 479 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 1.5" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.1" 3.2" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Bear Lake 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 ~919 GDD — county provides 1,506 GDD Excellent fit

Comfrey Planting Timeline — Bear Lake County, ID

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 31 May 31 – Jun 14
Harvest August 2 Aug 2 – Oct 11

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

Month-by-Month Timeline

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

123 days in Bear Lake County

Growing Tips for Comfrey in Bear Lake County

Direct sow Comfrey outdoors after May 24 in Bear Lake County when soil has warmed and frost danger has passed.

Bear Lake 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 Bear Lake County, ID?

Bear Lake County is in Zone 5a with an average last frost of May 24. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bear Lake County, ID?

Bear Lake County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 24 and first fall frost is September 24.

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Your Bear Lake County Garden Planner — Free

A 24-page printable planner built for Bear Lake 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 Bear Lake County, ID. 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.