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When to plant Garlic in Penobscot County County,

Plant Garlic in Penobscot County County, when soil hits 50°F — usually mid-spring. Continue planting through late spring for the spring crop. A second sowing from August 21 to September 4 extends the harvest into fall.

When to Plant Garlic in Penobscot County, ME

Garlic
Penobscot County, Maine Zone 5a June

June in the garden — Penobscot County, Maine

Welcome to June in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 10
Avg. first frost October 2
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 15.5 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.

Penobscot County, Maine is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 2, giving you a growing season of approximately 145 days.

At an elevation of 842 feet, Penobscot County receives approximately 38.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Garlic to ensure they mature before fall.

Penobscot County, ME (Zone 5a) Short season
145 days
Last Spring Frost May 10
145 growing days
First Fall Frost October 2

Penobscot County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.7

Drainage

Well Drained

Garlic Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 7 🍅 Harvest: Aug 6 – Oct 22
Recommended (50%) ✗ May not fit
Transplant: May 10 🍅 Harvest: Aug 9 – Oct 25
Safe Start (90%) ✗ May not fit
Transplant: May 25 🍅 Harvest: Aug 24 – Nov 9

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 Penobscot County

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

Soil pH

Your soil pH (4.8–6.7) is more acidic than Garlic prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). 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.

Garlic Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 2.4" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 2.2" 3.9" 0" ✅ Rainfall sufficient
Jun 2.2" 3.9" 0" ✅ Rainfall sufficient
Jul 2.2" 3.5" 0" ✅ Rainfall sufficient
Aug 2.2" 3.2" 0" ✅ Rainfall sufficient
Sep 2.2" 3.7" 0" ✅ Rainfall sufficient
Oct 2.2" 3.6" 0" ✅ Rainfall sufficient
Nov 3.2" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Penobscot 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 1,776 GDD May not mature

Garlic Planting Timeline — Penobscot County, ME

Garlic Planting Calendar

Activity When Date Range
Harvest November 20 Nov 20 – Feb 5
Fall Sowing August 21 Aug 21 – Sep 4

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

Month-by-Month Timeline

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

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: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

145 days in Penobscot County

Growing Tips for Garlic in Penobscot County

Direct sow Garlic outdoors after May 10 in Penobscot County when soil has warmed and frost danger has passed.

Your 145.0-day growing season in Penobscot 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 Penobscot County, ME?

Penobscot County is in Zone 5a with an average last frost of May 10. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.

What planting zone is Penobscot County, ME?

Penobscot County, Maine is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is October 2.

When should I plant Garlic in Penobscot County County, ?

In Penobscot County County, , plant Garlic after the last frost (around May 10) and before the first frost (around October 2). Best results when soil holds above 50°F.

What growing zone is Penobscot County County, for Garlic?

Penobscot County County sits in USDA Zone 5a. Garlic grows reliably in zones 3a through 9b, so it's a good fit here.

Can Garlic grow in Penobscot County County's climate?

Yes — Garlic grows well in Penobscot County County's temperate climate. Penobscot County County averages a 145-day frost-free season, with last frost around May 10 and first frost around October 2.

🌱

Your Penobscot County Garden Planner — Free

A 22-page printable planner built for Penobscot County (Zone 5a). 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 Penobscot County, ME. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.