Blog

When to Plant Blackberries in Ketchikan Gateway Borough, AK

Ketchikan Gateway Borough, Alaska Zone 7b May

Your May game plan for Ketchikan Gateway Borough, Alaska

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Ketchikan Gateway Borough, Alaska.

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

    Frost risk is low now in Ketchikan Gateway Borough, Alaska. If you've been covering beds overnight, you can stop.

Instant PDF download. No spam, unsubscribe any time.

Blackberries are vigorous bramble fruits that produce sweet-tart berries on thorny or thornless canes. They are prolific producers and relatively low-maintenance once established.

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 Blackberries to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Blackberries 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
Share this guide:

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) ✓ Fits season
Transplant: May 9
Recommended (50%) ✓ Fits season
Transplant: May 16
Safe Start (90%) ✓ Fits season
Transplant: Jun 3

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 Blackberries's growing requirements.

Soil pH

Your soil pH (5.0–6.7) overlaps with Blackberries's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Blackberries.

Organic Matter

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

How to Plant Blackberries

24"
Between Plants
72"
Between Rows

Plant Water Budget

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

Monthly Watering Guide for Blackberries

Blackberries needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Blackberries Needs Rainfall You Supplement Action
Jan 2.8" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 4.3" 2" 2.3" 🚿 Regular watering
May 4.3" 2.4" 1.9" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 6.6" 0" ✅ Rainfall sufficient
Aug 4.3" 9.5" 0" ✅ Rainfall sufficient
Sep 4.3" 11" 0" ✅ Rainfall sufficient
Oct 4.3" 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.

Blackberries 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.

Blackberries needs ~0 GDD — county provides 0 GDD May not mature

Blackberries Planting Timeline — Ketchikan Gateway Borough, AK

Blackberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 16 May 16 – May 30

· 24" apart · Rows 72" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

177 days in Ketchikan Gateway Borough

Growing Tips for Blackberries in Ketchikan Gateway Borough

Direct sow Blackberries 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 Blackberries (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant bare-root canes in spring. Provide a sturdy trellis system. Prune out spent fruiting canes after harvest. New canes fruit in their second year (floricanes).

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Blackberries in Ketchikan Gateway Borough, AK?

Ketchikan Gateway Borough is in Zone 7b with an average last frost of April 25. Plan your Blackberries 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.

🌱

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.

Instant PDF download. No spam, unsubscribe any time.

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

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