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When to plant Comfrey in Solano County County,

Solano County County's 298-day season only supports one Comfrey planting per year. Sow between February 16 and March 2 for the best chance at full maturity before December 3.

When to Plant Comfrey in Solano County, CA

Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.

Solano County, California is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 3, giving you a growing season of approximately 297 days.

At an elevation of 376 feet, Solano County receives approximately 40.4 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Comfrey may need afternoon shade and extra watering during peak heat.

Solano County, CA (Zone 9b) Year-round
297 days
Last Spring Frost February 9
297 growing days
First Fall Frost December 3
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Solano County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.3

Drainage

Well Drained

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 8.9" 0" ❄️ Dormant
Feb 4.3" 8.4" 0" ✅ Rainfall sufficient
Mar 4.3" 6.6" 0" ✅ Rainfall sufficient
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 1" 3.3" 🚿 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" 1.9" 2.4" 🚿 Regular watering
Nov 4.3" 3.3" 1" 💧 Light watering
Dec 4.3" 7.1" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Solano County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Comfrey Planting Timeline — Solano County, CA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors February 16 Feb 16 – Mar 2
Harvest April 20 Apr 20 – Jun 29

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
August
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 9b

📆 Growing Season

297 days in Solano County

Growing Tips for Solano County

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 Solano County, CA?

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

What planting zone is Solano County, CA?

Solano County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 3.

When should I plant Comfrey in Solano County County, ?

In Solano County County, , plant Comfrey after the last frost (around February 9) and before the first frost (around December 3). Best results when soil holds above 50°F.

What growing zone is Solano County County, for Comfrey?

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

Can Comfrey grow in Solano County County's climate?

Yes — Comfrey grows well in Solano County County's temperate climate. Solano County County averages a 298-day frost-free season, with last frost around February 9 and first frost around December 3.

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Your Solano County Garden Planner — Free

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

Sources & credits

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