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When to Plant Garlic in Ketchikan Gateway Borough, AK

Ketchikan Gateway Borough, Alaska Zone 7b May

Top priorities for Ketchikan Gateway Borough, Alaska gardeners in May

Your garden in Ketchikan Gateway Borough, Alaska is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 25
Avg. first frost October 19
Soil temp (4") 64°F
Watering High
Pest pressure Moderate
Daylight 15.9 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.

Ketchikan Gateway Borough, Alaska is in USDA Zone 7b. The average last spring frost is April 25 and the first fall frost is October 19, giving you a growing season of approximately 177 days.

At an elevation of 1,212 feet, Ketchikan Gateway Borough receives approximately 57.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 65°F, so choose short-season varieties of Garlic to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Garlic root diseases.

Ketchikan Gateway Borough, AK (Zone 7b) Moderate season
177 days
Last Spring Frost April 25
177 growing days
First Fall Frost October 19

Ketchikan Gateway Borough Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 18 🍅 Harvest: Jul 18 – Nov 28
Recommended (50%) ✗ May not fit
Transplant: Apr 25 🍅 Harvest: Jul 25 – Dec 5
Safe Start (90%) ✗ May not fit
Transplant: May 13 🍅 Harvest: Aug 12 – Dec 23

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 Ketchikan Gateway Borough

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

Soil pH

Your soil pH (5.0–6.7) is more acidic than Garlic prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Garlic.

Organic Matter

Organic matter is excellent (5.9%) — Garlic will thrive.

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
1.4″/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 2.8" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.2" 2" 0.2" 💧 Light watering
May 2.2" 2.4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.5" 0" ✅ Rainfall sufficient
Jul 2.2" 6.6" 0" ✅ Rainfall sufficient
Aug 2.2" 9.5" 0" ✅ Rainfall sufficient
Sep 2.2" 11" 0" ✅ Rainfall sufficient
Oct 2.2" 6.6" 0" ✅ Rainfall sufficient
Nov 3.8" 0" ❄️ Dormant
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ketchikan Gateway Borough). 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 ~0 GDD — county provides 0 GDD May not mature

Garlic Planting Timeline — Ketchikan Gateway Borough, AK

Garlic Planting Calendar

Activity When Date Range
Fall Sowing September 7 Sep 7 – Sep 21

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

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 7b

📆 Growing Season

177 days in Ketchikan Gateway Borough

Growing Tips for Garlic in Ketchikan Gateway Borough

Direct sow Garlic outdoors after April 25 in Ketchikan Gateway Borough when soil has warmed and frost danger has passed.

Your 177.0-day growing season in Ketchikan Gateway Borough 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.

With 58" of annual rainfall in Ketchikan Gateway Borough, ensure good drainage for Garlic — excess moisture can promote root rot and fungal diseases.

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 Ketchikan Gateway Borough, AK?

Ketchikan Gateway Borough is in Zone 7b with an average last frost of April 25. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ketchikan Gateway Borough, AK?

Ketchikan Gateway Borough, Alaska is in USDA Hardiness Zone 7b. The average last spring frost is April 25 and first fall frost is October 19.

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Your Ketchikan Gateway Borough Garden Planner — Free

A 24-page printable planner built for Ketchikan Gateway Borough (Zone 7b). 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 Ketchikan Gateway Borough, AK. Local conditions may vary. Last updated: May 2026.

Sources & credits

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