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When to plant Comfrey in Nelson, CA

Plant Comfrey in Nelson during the brief April 27–May 11 window. With 204 frost-free days, fall plantings can't mature before November 10.

When to Plant Comfrey in Nelson, CA

Butte County, California Zone 9b July

Your July game plan for Butte County, California

July is a pivotal month for Butte County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 20
Avg. first frost November 10
Soil temp (4") 95°F
Watering Critical
Pest pressure High
Daylight 14.5 hrs
  1. Collect comfrey at their peak

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

A few tasks this July that'll pay off in 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.

Nelson, California is in USDA Zone 9b. The average last spring frost is April 20 and the first fall frost is November 10, giving you a growing season of approximately 204 days.

At an elevation of 144 feet, Butte County receives approximately 44.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Comfrey during the growing season.

Nelson, CA (Zone 9b) Long season
204 days
Last Spring Frost April 20
204 growing days
First Fall Frost November 10

Nelson Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Comfrey Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Transplant: Apr 2 🍅 Harvest: Jun 4 – Aug 13
Recommended (50%) ✓ Fits season (64 days to spare)
Transplant: Apr 27 🍅 Harvest: Jun 29 – Sep 7
Safe Start (90%) ✓ Fits season (64 days to spare)
Transplant: May 31 🍅 Harvest: Aug 2 – Oct 11

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 Nelson

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

Soil pH

Your soil pH (6.8–7.7) is more alkaline than Comfrey prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Comfrey.

Organic Matter

Organic matter is moderate (2.5%). 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 204-day season

Sow every 6.9 weeks. Last sowing by Aug 12 to harvest before frost.

Comfrey Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 823 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 9.7" 0" ❄️ Dormant
Feb 9.9" 0" ❄️ Dormant
Mar 6.9" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 1.1" 3.2" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 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" 2.1" 2.2" 🚿 Regular watering
Nov 4.3" 3.7" 0.6" 💧 Light watering
Dec 7.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Butte 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 3,570 GDD Excellent fit

Comfrey Planting Timeline — Nelson, CA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 27 Apr 27 – May 11
Harvest June 29 Jun 29 – Sep 7

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

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 9b

📆 Growing Season

204 days in Butte County

Growing Tips for Comfrey in Nelson

Direct sow Comfrey outdoors after April 20 in Butte 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 →

When should I plant Comfrey in Nelson, CA?

In Nelson, CA, plant Comfrey after the last frost (around April 20) and before the first frost (around November 10). Best results when soil holds above 50°F.

What growing zone is Nelson, CA for Comfrey?

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

Can Comfrey grow in Nelson's climate?

Yes — Comfrey grows well in Nelson's temperate climate. Nelson averages a 204-day frost-free season, with last frost around April 20 and first frost around November 10.

🌱

Your Butte County Garden Planner — Free

A 22-page printable planner built for Butte 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 Butte County, CA. Local conditions may vary. Last updated: July 2026.