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When to plant Comfrey in Anchorage Municipality, AK

Anchorage Municipality sits in cold Zone 5a. Plant Comfrey May 22–June 5 for the single annual harvest; the September 19 first frost closes the window.

When to Plant Comfrey in Anchorage Municipality, AK

Anchorage Municipality, Alaska Zone 5a July

Your July gardening checklist

If you only do a handful of things in the garden this July, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 15
Avg. first frost September 19
Soil temp (4") 64°F
Watering High
Pest pressure High
Daylight 18.1 hrs
  1. Start harvesting comfrey

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Looking ahead to August
  • First harvests: 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.

Anchorage Municipality, Alaska is in USDA Zone 5a. The average last spring frost is May 15 and the first fall frost is September 19, giving you a growing season of approximately 127 days.

At an elevation of 2,537 feet, Anchorage Municipality receives approximately 20.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 71°F, so choose short-season varieties of Comfrey to ensure they mature before fall.

Anchorage Municipality, AK (Zone 5a) Short season
127 days
Last Spring Frost May 15
127 growing days
First Fall Frost September 19

Anchorage Municipality Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.5

Drainage

Well Drained

Comfrey Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 11 🍅 Harvest: Jul 13 – Sep 21
Recommended (50%) ✗ May not fit
Transplant: May 22 🍅 Harvest: Jul 24 – Oct 2
Safe Start (90%) ✗ May not fit
Transplant: Jun 9 🍅 Harvest: Aug 11 – Oct 20

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 Anchorage Municipality

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

Soil pH

Your soil pH (4.9–6.5) is more acidic than Comfrey prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Anchorage Municipality is excellent for Comfrey — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Comfrey.

Organic Matter

Organic matter is excellent (5.2%) — Comfrey will thrive.

How to Plant Comfrey

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

Succession Planting Comfrey

2
successive plantings in your 127-day season

Sow every 6.9 weeks. Last sowing by Jun 21 to harvest before frost.

Comfrey Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 29 gal / 100 sq ft

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" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 0.8" 0" ❄️ Dormant
Apr 0.6" 0" ❄️ Dormant
May 4.3" 0.9" 3.4" 🚿 Regular watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2.6" 1.7" 💧 Light watering
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 2.4" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Anchorage Municipality). 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 ~244 GDD — county provides 412 GDD Excellent fit

Comfrey Planting Timeline — Anchorage Municipality, AK

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 22 May 22 – Jun 5
Harvest July 24 Jul 24 – Oct 2

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 Harvest
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_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

127 days in Anchorage Municipality

Growing Tips for Comfrey in Anchorage Municipality

Direct sow Comfrey outdoors after May 15 in Anchorage Municipality when soil has warmed and frost danger has passed.

Anchorage Municipality receives only 20" 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 Anchorage Municipality, AK?

Anchorage Municipality is in Zone 5a with an average last frost of May 15. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Anchorage Municipality, AK?

Anchorage Municipality, Alaska is in USDA Hardiness Zone 5a. The average last spring frost is May 15 and first fall frost is September 19.

When should I plant Comfrey in Anchorage Municipality, AK?

In Anchorage Municipality, AK, plant Comfrey after the last frost (around May 15) and before the first frost (around September 19). Best results when soil holds above 50°F.

What growing zone is Anchorage Municipality, AK for Comfrey?

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

Can Comfrey grow in Anchorage Municipality's climate?

Yes — Comfrey grows well in Anchorage Municipality's temperate climate. Anchorage Municipality averages a 127-day frost-free season, with last frost around May 15 and first frost around September 19.

🌱

Your Anchorage Municipality Garden Planner — Free

A 22-page printable planner built for Anchorage Municipality (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 Anchorage Municipality, AK. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.