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When to Plant Comfrey in Carson, WA

Carson, WA Zone 8a June

Your June game plan for Carson, WA

A quick June briefing for Carson, WA gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 18
Avg. first frost October 19
Soil temp (4") 76°F
Watering High
Pest pressure High
Daylight 15.5 hrs
  1. Pick comfrey

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

July will be here before you know it — start on
  • 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.

Carson, Washington is in USDA Zone 8a. The average last spring frost is April 18 and the first fall frost is October 19, giving you a growing season of approximately 184 days.

At an elevation of 16 feet, Skamania County receives approximately 43 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Comfrey to ensure they mature before fall.

Carson, WA (Zone 8a) Moderate season
184 days
Last Spring Frost April 18
184 growing days
First Fall Frost October 19
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Carson Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Comfrey Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 30
Recommended (50%) ✓ Fits season (44 days to spare)
Transplant: Apr 25 🍅 Harvest: Jun 27 – Sep 5
Safe Start (90%) ✓ Fits season (52 days to spare)
Transplant: May 17 🍅 Harvest: Jul 19 – Sep 27

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 Carson

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

Soil pH

Your soil pH (5.6–6.2) is more acidic than Comfrey prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Comfrey will thrive.

How to Plant Comfrey

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

Succession Planting Comfrey

3
successive plantings in your 184-day season

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

Comfrey Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 30 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 4.3" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 2.1" 2.2" 🚿 Regular watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 0.7" 3.6" 🚿 Regular watering
Aug 4.3" 0.7" 3.6" 🚿 Regular watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 7.4" 0" ❄️ Dormant
Dec 7.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Skamania 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 ~694 GDD — county provides 1,702 GDD Excellent fit

Comfrey Planting Timeline — Carson, WA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 25 Apr 25 – May 9
Harvest June 27 Jun 27 – Sep 5

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
June Harvest
July Harvest
August Harvest
September Harvest
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: too_acidic

🗺️ USDA Zone

Zone 8a

📆 Growing Season

184 days in Skamania County

Growing Tips for Comfrey in Carson

Direct sow Comfrey outdoors after April 18 in Skamania 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 →

🌱

Your Skamania County Garden Planner — Free

A 22-page printable planner built for Skamania County (Zone 8a). 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 Skamania County, WA. Local conditions may vary. Last updated: June 2026.