Blog

When to Plant Comfrey in Navajo County, AZ

Navajo County, Arizona Zone 7a May

Your May gardening checklist

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Navajo County, Arizona.

Avg. last frost May 2
Avg. first frost October 16
Soil temp (4") 47°F
Watering Critical
Pest pressure Low
Daylight 13.9 hrs
  1. Transplant comfrey outside

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

Instant PDF download. No spam, unsubscribe any time.

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

Navajo County, Arizona is in USDA Zone 7a. The average last spring frost is May 2 and the first fall frost is October 16, giving you a growing season of approximately 167 days.

At an elevation of 5,528 feet, Navajo County receives approximately 15.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°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. With low rainfall, drip irrigation is essential for growing Comfrey successfully. Mulch heavily to conserve soil moisture.

Navajo County, AZ (Zone 7a) Moderate season
167 days
Last Spring Frost May 2
167 growing days
First Fall Frost October 16

Navajo County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12
Recommended (50%) ✓ Fits season (27 days to spare)
Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19
Safe Start (90%) ✓ Fits season (26 days to spare)
Transplant: May 25 🍅 Harvest: Jul 27 – Oct 5

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 Navajo County

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

Soil pH

Your soil pH (7.3–8.3) is more alkaline than Comfrey prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Navajo 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

3
successive plantings in your 167-day season

Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,610 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 1.3" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 0.9" 0" ❄️ Dormant
Apr 0.6" 0" ❄️ Dormant
May 4.3" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.6" 3.7" 🚿 Regular watering
Jul 4.3" 2.4" 1.9" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 4.3" 1.3" 3" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Navajo 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 ~1,538 GDD — county provides 3,423 GDD Excellent fit

Comfrey Planting Timeline — Navajo County, AZ

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 9 May 9 – May 23
Harvest July 11 Jul 11 – Sep 19

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
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 7a

📆 Growing Season

167 days in Navajo County

Growing Tips for Comfrey in Navajo County

Direct sow Comfrey outdoors after May 02 in Navajo County when soil has warmed and frost danger has passed.

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

Navajo 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 Navajo County, AZ?

Navajo County is in Zone 7a with an average last frost of May 2. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Navajo County, AZ?

Navajo County, Arizona is in USDA Hardiness Zone 7a. The average last spring frost is May 2 and first fall frost is October 16.

🌱

Your Navajo County Garden Planner — Free

A 24-page printable planner built for Navajo County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Navajo 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.