When to Plant Garlic in San Juan County, NM
Your May planting checklist for San Juan County, New Mexico
Welcome to May in Zone 7a. These are the moves that will have the biggest impact on your growing season.
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.
San Juan County, New Mexico is in USDA Zone 7a. The average last spring frost is May 12 and the first fall frost is October 6, giving you a growing season of approximately 147 days.
At an elevation of 8,301 feet, San Juan County receives approximately 14.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 87°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.
San Juan County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.3-8.5
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 San Juan County
How your county's soil matches Garlic's growing requirements.
Soil pH
Your soil pH (7.3–8.5) is more alkaline than Garlic prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in San Juan 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 | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 0.8" | 0" | ❄️ Dormant |
| Apr | — | 0.5" | 0" | ❄️ Dormant |
| May | 2.2" | 0.3" | 1.9" | 🚿 Regular watering |
| Jun | 2.2" | 0.5" | 1.7" | 🚿 Regular watering |
| Jul | 2.2" | 2.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| Nov | — | 0.8" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in San Juan 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 — San Juan County, NM
Garlic Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Fall Sowing | August 25 | Aug 25 – Sep 8 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | — |
| July | — |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Only during dry spells
📅 Days to Maturity
90–240 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 7a
📆 Growing Season
147 days in San Juan County
Growing Tips for Garlic in San Juan County
Direct sow Garlic outdoors after May 12 in San Juan County when soil has warmed and frost danger has passed.
Sandy soil in San Juan 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 147.0-day growing season in San Juan 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
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Check more plant combinations with our Companion Planting Checker →
Garlic in Other Locations
Frequently Asked Questions
When should I plant Garlic in San Juan County, NM?
San Juan County is in Zone 7a with an average last frost of May 12. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Juan County, NM?
San Juan County, New Mexico is in USDA Hardiness Zone 7a. The average last spring frost is May 12 and first fall frost is October 6.
Your San Juan County Garden Planner — Free
A 24-page printable planner built for San Juan 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.