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When to Plant Garlic in Modoc County, CA

Modoc County, California Zone 6b May

Your May gardening checklist

A quick May briefing for Modoc County, California gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 31
Avg. first frost September 21
Soil temp (4") 57°F
Watering Critical
Pest pressure Low
Daylight 14.3 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.

Modoc County, California is in USDA Zone 6b. The average last spring frost is May 31 and the first fall frost is September 21, giving you a growing season of approximately 113 days.

At an elevation of 2,205 feet, Modoc County receives approximately 28.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Garlic to ensure they mature before fall.

Modoc County, CA (Zone 6b) Short season
113 days
Last Spring Frost May 31
113 growing days
First Fall Frost September 21

Modoc County Soil Profile

Soil Type

Loam

Soil pH

5.9-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 19 🍅 Harvest: Aug 18 – Dec 1
Recommended (50%) ✗ May not fit
Transplant: May 31 🍅 Harvest: Aug 30 – Dec 13
Safe Start (90%) ✓ Fits season (288 days to spare)
Transplant: Jun 19 🍅 Harvest: Sep 18 – Jan 1

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 Modoc County

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

Soil pH

Your soil pH (5.9–7.4) overlaps with Garlic's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Modoc County is excellent for Garlic — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Garlic.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help 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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 5.6" 0" ❄️ Dormant
Feb 5.8" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 2.2" 0.7" 1.5" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.4" 1.8" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 2.7" 0" ❄️ Dormant
Dec 5.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Modoc 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 ~2,021 GDD — county provides 1,384 GDD May not mature

Garlic Planting Timeline — Modoc County, CA

Garlic Planting Calendar

Activity When Date Range
Fall Sowing August 10 Aug 10 – Aug 24

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

90–240 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

113 days in Modoc County

Growing Tips for Garlic in Modoc County

Direct sow Garlic outdoors after May 31 in Modoc County when soil has warmed and frost danger has passed.

Your 113.0-day growing season in Modoc 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 Modoc County, CA?

Modoc County is in Zone 6b with an average last frost of May 31. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.

What planting zone is Modoc County, CA?

Modoc County, California is in USDA Hardiness Zone 6b. The average last spring frost is May 31 and first fall frost is September 21.

🌱

Your Modoc County Garden Planner — Free

A 24-page printable planner built for Modoc County (Zone 6b). 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 Modoc County, CA. 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.