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When to Plant Comfrey in Pinal County, AZ

Pinal County, Arizona Zone 9a May

Your May gardening checklist

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

Avg. last frost February 23
Avg. first frost November 27
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. Basket week: comfrey

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

To set up a strong June, finish these tasks
  • 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.

Pinal County, Arizona is in USDA Zone 9a. The average last spring frost is February 23 and the first fall frost is November 27, giving you a growing season of approximately 277 days.

At an elevation of 3,959 feet, Pinal County receives approximately 15.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98°F, so Comfrey may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Comfrey will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Comfrey successfully. Mulch heavily to conserve soil moisture.

Pinal County, AZ (Zone 9a) Year-round
277 days
Last Spring Frost February 23
277 growing days
First Fall Frost November 27

Pinal County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (145 days to spare)
Transplant: Feb 17 🍅 Harvest: Apr 21 – Jun 30
Recommended (50%) ✓ Fits season (137 days to spare)
Transplant: Mar 2 🍅 Harvest: May 4 – Jul 13
Safe Start (90%) ✓ Fits season (125 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 2 – Aug 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 Pinal County

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

Soil pH

Your soil pH (7.0–8.6) is more alkaline than Comfrey prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Comfrey.

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Comfrey.

How to Plant Comfrey

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

Succession Planting Comfrey

5
successive plantings in your 277-day season

Sow every 6.9 weeks. Last sowing by Aug 29 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 3,151 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1" 0" ❄️ Dormant
Feb 4.3" 1" 3.3" 🚿 Regular watering
Mar 4.3" 0.8" 3.5" 🚿 Regular watering
Apr 4.3" 0.5" 3.8" 🚿 Regular watering
May 4.3" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.5" 3.8" 🚿 Regular watering
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 1.5" 2.8" 🚿 Regular watering
Nov 4.3" 0.8" 3.5" 🚿 Regular watering
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Pinal 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 ~1,762 GDD — county provides 6,533 GDD Excellent fit

Comfrey Planting Timeline — Pinal County, AZ

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors March 2 Mar 2 – Mar 16
Harvest May 4 May 4 – Jul 13

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

Month-by-Month Timeline

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

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: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

277 days in Pinal County

Growing Tips for Comfrey in Pinal County

Direct sow Comfrey outdoors after February 23 in Pinal County when soil has warmed and frost danger has passed.

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

With summer highs reaching 98°F in Pinal County, provide afternoon shade for Comfrey and water deeply in the morning.

Pinal County receives only 16" 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 Pinal County, AZ?

Pinal County is in Zone 9a with an average last frost of February 23. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pinal County, AZ?

Pinal County, Arizona is in USDA Hardiness Zone 9a. The average last spring frost is February 23 and first fall frost is November 27.

🌱

Your Pinal County Garden Planner — Free

A 24-page printable planner built for Pinal 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 Pinal County, AZ. 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.