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When to Plant Comfrey in Del Norte County, CA

Del Norte County, California Zone 9b May

Your May planting checklist for Del Norte County, California

A quick May briefing for Del Norte County, California gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 27
Avg. first frost November 20
Soil temp (4") 71°F
Watering Critical
Pest pressure High
Daylight 14.4 hrs
June 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.

Del Norte County, California is in USDA Zone 9b. The average last spring frost is March 27 and the first fall frost is November 20, giving you a growing season of approximately 238 days.

At an elevation of 72 feet, Del Norte County receives approximately 43.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 89°F, providing good warmth for Comfrey during the growing season. Sandy soil warms quickly in spring — great for early planting — but Comfrey will need more frequent watering and organic matter to retain nutrients.

Del Norte County, CA (Zone 9b) Long season
238 days
Last Spring Frost March 27
238 growing days
First Fall Frost November 20

Del Norte County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.9-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (97 days to spare)
Transplant: Mar 12 🍅 Harvest: May 14 – Jul 23
Recommended (50%) ✓ Fits season (98 days to spare)
Transplant: Apr 3 🍅 Harvest: Jun 5 – Aug 14
Safe Start (90%) ✓ Fits season (87 days to spare)
Transplant: May 11 🍅 Harvest: Jul 13 – Sep 21

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 Del Norte County

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

Soil pH

Your soil pH (5.9–7.0) overlaps with Comfrey's range (6.0–7.0), though not a perfect match.

Soil Texture

Sandy soil in Del Norte County warms quickly in spring but drains fast. Comfrey will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Comfrey.

How to Plant Comfrey

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

Succession Planting Comfrey

4
successive plantings in your 238-day season

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 481 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 8.3" 0" ❄️ Dormant
Feb 9.9" 0" ❄️ Dormant
Mar 4.3" 5.8" 0" ✅ Rainfall sufficient
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 1.1" 3.2" 🚿 Regular watering
Jun 4.3" 0.3" 4" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.4" 3.9" 🚿 Regular watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 4.3" 4.7" 0" ✅ Rainfall sufficient
Dec 7.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Del Norte 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 ~1,256 GDD — county provides 3,986 GDD Excellent fit

Comfrey Planting Timeline — Del Norte County, CA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 3 Apr 3 – Apr 17
Harvest June 5 Jun 5 – Aug 14

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

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 9b

📆 Growing Season

238 days in Del Norte County

Growing Tips for Comfrey in Del Norte County

Direct sow Comfrey outdoors after March 27 in Del Norte County when soil has warmed and frost danger has passed.

Sandy soil in Del Norte County dries quickly — mulch Comfrey with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

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 Del Norte County, CA?

Del Norte County is in Zone 9b with an average last frost of March 27. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Del Norte County, CA?

Del Norte County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 27 and first fall frost is November 20.

🌱

Your Del Norte County Garden Planner — Free

A 24-page printable planner built for Del Norte County (Zone 9b). 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 Del Norte County, CA. 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.