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When to Plant Comfrey in Kings County, CA

Kings County, California Zone 9a May

What to do in May

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

Avg. last frost February 14
Avg. first frost December 2
Soil temp (4") 72°F
Watering Critical
Pest pressure High
Daylight 13.9 hrs
  1. Pick comfrey

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

June prep starts now
  • 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.

Kings County, California is in USDA Zone 9a. The average last spring frost is February 14 and the first fall frost is December 2, giving you a growing season of approximately 291 days.

At an elevation of 2,065 feet, Kings County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Comfrey may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Comfrey successfully. Mulch heavily to conserve soil moisture.

Kings County, CA (Zone 9a) Year-round
291 days
Last Spring Frost February 14
291 growing days
First Fall Frost December 2
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Kings County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (157 days to spare)
Transplant: Feb 7 🍅 Harvest: Apr 11 – Jun 20
Recommended (50%) ✓ Fits season (151 days to spare)
Transplant: Feb 21 🍅 Harvest: Apr 25 – Jul 4
Safe Start (90%) ✓ Fits season (149 days to spare)
Transplant: Mar 15 🍅 Harvest: May 17 – Jul 26

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 Kings County

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

Soil pH

Your soil pH (6.5–7.4) overlaps with Comfrey's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Comfrey.

How to Plant Comfrey

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

Succession Planting Comfrey

5
successive plantings in your 291-day season

Sow every 6.9 weeks. Last sowing by Sep 03 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,275 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 3.6" 0" ❄️ Dormant
Feb 4.3" 4" 0.3" 💧 Light watering
Mar 4.3" 3.2" 1.1" 💧 Light watering
Apr 4.3" 1.4" 2.9" 🚿 Regular watering
May 4.3" 0.5" 3.8" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.2" 4.1" 🚿 Regular watering
Oct 4.3" 0.7" 3.6" 🚿 Regular watering
Nov 4.3" 1.9" 2.4" 🚿 Regular watering
Dec 4.3" 3.2" 1.1" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Kings 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 ~1,988 GDD — county provides 7,738 GDD Excellent fit

Comfrey Planting Timeline — Kings County, CA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors February 21 Feb 21 – Mar 7
Harvest April 25 Apr 25 – Jul 4

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

291 days in Kings County

Growing Tips for Comfrey in Kings County

Direct sow Comfrey outdoors after February 14 in Kings County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Kings County, provide afternoon shade for Comfrey and water deeply in the morning.

Kings County receives only 19" 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 Kings County, CA?

Kings County is in Zone 9a with an average last frost of February 14. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kings County, CA?

Kings County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 14 and first fall frost is December 2.

🌱

Your Kings County Garden Planner — Free

A 24-page printable planner built for Kings County (Zone 9a). 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 Kings 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.