When to Plant Garlic in Pima County, AZ
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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.
Pima County, Arizona is in USDA Zone 9b. The average last spring frost is April 1 and the first fall frost is November 9, giving you a growing season of approximately 222 days.
At an elevation of 4,327 feet, Pima County receives approximately 14.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103°F, so Garlic may need afternoon shade and extra watering during peak heat. 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.
Pima County Soil Profile
Soil Type
Sandy Loam
Soil pH
6.8-8.3
Drainage
Well Drained
Plant Planting Risk Windows
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 Pima County
How your county's soil matches Garlic's growing requirements.
Soil pH
Your soil pH (6.8–8.3) is more alkaline than Garlic prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Pima 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 (0.9%). Add 2-3 inches of compost before planting Garlic.
How to Plant Garlic
Fall planting: Sow 6 weeks before your first frost date for a fall harvest.
Plant Water Budget
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 | — | 0.9" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 0.7" | 0" | ❄️ Dormant |
| Apr | 2.2" | 0.5" | 1.7" | 🚿 Regular watering |
| May | 2.2" | 0.4" | 1.8" | 🚿 Regular watering |
| Jun | 2.2" | 0.5" | 1.7" | 🚿 Regular watering |
| Jul | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Oct | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Nov | 2.2" | 0.7" | 1.5" | 🚿 Regular watering |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Pima 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 Planting Timeline — Pima County, AZ
Garlic Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Fall Sowing | September 28 | Sep 28 – Oct 12 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | — |
| July | — |
| August | — |
| September | Fall Sowing |
| October | Fall Sowing |
| November | — |
| December | — |
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 9b
📆 Growing Season
222 days in Pima County
Growing Tips for Garlic in Pima County
Direct sow Garlic outdoors after April 01 in Pima County when soil has warmed and frost danger has passed.
Sandy soil in Pima County dries quickly — mulch Garlic with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 103°F in Pima County, provide afternoon shade for Garlic and water deeply in the morning.
Your 222.0-day growing season in Pima 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
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Garlic in Other Locations
Frequently Asked Questions
When should I plant Garlic in Pima County, AZ?
Pima County is in Zone 9b with an average last frost of April 1. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pima County, AZ?
Pima County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is April 1 and first fall frost is November 9.
Your Pima County Garden Planner — Free
A 24-page printable planner built for Pima 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.