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When to Plant Sunflower in Kodiak Island Borough, AK

Kodiak Island Borough, Alaska Zone 7b May

Your May planting checklist for Kodiak Island Borough, Alaska

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

Avg. last frost May 13
Avg. first frost September 29
Soil temp (4") 58°F
Watering High
Pest pressure Low
Daylight 16.3 hrs
  1. Time to transplant sunflower

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

  2. Put sunflower seeds straight in the ground

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Kodiak Island Borough, Alaska is in USDA Zone 7b. The average last spring frost is May 13 and the first fall frost is September 29, giving you a growing season of approximately 139 days.

At an elevation of 2,281 feet, Kodiak Island Borough receives approximately 27.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 60°F, so choose short-season varieties of Sunflower to ensure they mature before fall.

Kodiak Island Borough, AK (Zone 7b) Short season
139 days
Last Spring Frost May 13
139 growing days
First Fall Frost September 29

Kodiak Island Borough Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (14 days to spare)
Start indoors: Mar 14 Transplant: May 16 🍅 Harvest: Jul 25 – Sep 12
Recommended (50%) ✓ Fits season (6 days to spare)
Start indoors: Mar 25 Transplant: May 27 🍅 Harvest: Aug 5 – Sep 23
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Apr 6 Transplant: Jun 8 🍅 Harvest: Aug 17 – Oct 5

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 Kodiak Island Borough

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

Soil pH

Your soil pH (5.1–6.5) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Kodiak Island Borough is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Sunflower prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is excellent (5.3%) — Sunflower will thrive.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

2
successive plantings in your 139-day season

Sow every 8 weeks. Last sowing by Jun 21 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Sunflower

Sunflower 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 Sunflower Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 0.8" 0" ❄️ Dormant
May 2.2" 1.4" 0.8" 💧 Light watering
Jun 2.2" 2.4" 0" ✅ Rainfall sufficient
Jul 2.2" 3.2" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 5" 0" ✅ Rainfall sufficient
Oct 3.6" 0" ❄️ Dormant
Nov 1.9" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Kodiak Island Borough). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sunflower 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.

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

Sunflower Planting Timeline — Kodiak Island Borough, AK

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors May 27 May 27 – Jun 10
Direct Sow May 20 May 20 – Jun 10
Harvest August 5 Aug 5 – Sep 23

Plant 1" deep · 18" apart · Rows 30" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7b

📆 Growing Season

139 days in Kodiak Island Borough

Growing Tips for Sunflower in Kodiak Island Borough

Direct sow Sunflower outdoors after May 13 in Kodiak Island Borough when soil has warmed and frost danger has passed.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Kodiak Island Borough, AK?

Kodiak Island Borough is in Zone 7b with an average last frost of May 13. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kodiak Island Borough, AK?

Kodiak Island Borough, Alaska is in USDA Hardiness Zone 7b. The average last spring frost is May 13 and first fall frost is September 29.

🌱

Your Kodiak Island Borough Garden Planner — Free

A 24-page printable planner built for Kodiak Island 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 Kodiak Island 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.