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When to Plant Garlic in Navajo County, AZ

Navajo County, Arizona Zone 7a May

What to do in May

Here's what deserves your attention in Navajo County, Arizona this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

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

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Garlic is a pungent allium planted in fall and harvested the following summer. Hardneck varieties produce edible flower stalks (scapes) and are more cold-hardy.

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 Garlic during the growing season. Sandy soil warms quickly in spring — great for early planting — but Garlic will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Garlic 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
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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) ✗ May not fit
Transplant: Apr 25 🍅 Harvest: Jul 25 – Dec 5
Recommended (50%) ✗ May not fit
Transplant: May 2 🍅 Harvest: Aug 1 – Dec 12
Safe Start (90%) ✗ May not fit
Transplant: May 18 🍅 Harvest: Aug 17 – Dec 28

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 Garlic's growing requirements.

Soil pH

Your soil pH (7.3–8.3) is more alkaline than Garlic prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Garlic.

Organic Matter

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

How to Plant Garlic

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 451 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Garlic

Garlic needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Garlic 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 2.2" 0.3" 1.9" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 2.4" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.2" 1.3" 0.9" 💧 Light 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.

Garlic 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.

Garlic needs ~3,382 GDD — county provides 3,423 GDD Good fit

Garlic Planting Timeline — Navajo County, AZ

Garlic Planting Calendar

Activity When Date Range
Fall Sowing September 4 Sep 4 – Sep 18

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June
July
August
September Fall Sowing
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

90–240 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

167 days in Navajo County

Growing Tips for Garlic in Navajo County

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

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

Your 167.0-day growing season in Navajo County is tight for Garlic (90.0-240.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Garlic in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant individual cloves pointed end up in fall, 6 weeks before ground freezes. Mulch heavily with straw. Harvest when lower leaves begin to brown but 5-6 green leaves remain.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Garlic in Navajo County, AZ?

Navajo County is in Zone 7a with an average last frost of May 2. Plan your Garlic 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.

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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.

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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 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.