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When to Plant Comfrey in Skagit County, WA

Skagit County, Washington Zone 8b May

May in Skagit County, Washington — your action list

Each item below is timed to Skagit County, Washington's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 3
Avg. first frost October 28
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 15 hrs
A few tasks this May that'll pay off in June
  • 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.

Skagit County, Washington is in USDA Zone 8b. The average last spring frost is April 3 and the first fall frost is October 28, giving you a growing season of approximately 208 days.

At an elevation of 232 feet, Skagit County receives approximately 42.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Comfrey during the growing season.

Skagit County, WA (Zone 8b) Long season
208 days
Last Spring Frost April 3
208 growing days
First Fall Frost October 28
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Skagit County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (71 days to spare)
Transplant: Mar 30 🍅 Harvest: Jun 1 – Aug 10
Recommended (50%) ✓ Fits season (68 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 12 – Aug 21
Safe Start (90%) ✓ Fits season (59 days to spare)
Transplant: May 12 🍅 Harvest: Jul 14 – Sep 22

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 Skagit County

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

Soil pH

Your soil pH (5.6–6.6) overlaps with Comfrey's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — Comfrey will thrive.

How to Plant Comfrey

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

Succession Planting Comfrey

4
successive plantings in your 208-day season

Sow every 6.9 weeks. Last sowing by Jul 30 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 263 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 6.5" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 0.7" 3.6" 🚿 Regular watering
Aug 4.3" 0.7" 3.6" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 6.9" 0" ❄️ Dormant
Dec 6.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Skagit 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 ~1,312 GDD — county provides 3,640 GDD Excellent fit

Comfrey Planting Timeline — Skagit County, WA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 10 Apr 10 – Apr 24
Harvest June 12 Jun 12 – Aug 21

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 8b

📆 Growing Season

208 days in Skagit County

Growing Tips for Comfrey in Skagit County

Direct sow Comfrey outdoors after April 03 in Skagit County when soil has warmed and frost danger has passed.

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 Skagit County, WA?

Skagit County is in Zone 8b with an average last frost of April 3. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Skagit County, WA?

Skagit County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 3 and first fall frost is October 28.

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Your Skagit County Garden Planner — Free

A 24-page printable planner built for Skagit County (Zone 8b). 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 Skagit County, WA. 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.