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When to Plant Mizuna in Kodiak Island Borough, AK

Kodiak Island Borough, Alaska Zone 7b May

Kodiak Island Borough, Alaska gardeners: here's your May plan

Each item below is timed to Kodiak Island Borough, Alaska's frost dates and soil temperatures. Skip nothing, stress about nothing.

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 mizuna

    Your last frost (May 13) has passed. These warm-season crops can handle outdoor soil now.

Looking ahead to June
  • Starting indoors: mizuna
  • First harvests: mizuna

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Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.

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 Mizuna 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 (84 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jun 6 – Jul 4
Recommended (50%) ✓ Fits season (76 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jun 17 – Jul 15
Safe Start (90%) ✓ Fits season (86 days to spare)
Start indoors: Apr 20 Transplant: May 25 🍅 Harvest: Jun 29 – Jul 27

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 Mizuna's growing requirements.

Soil pH

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

Soil Texture

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

Drainage

Drainage is adequate for Mizuna.

Organic Matter

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

How to Plant Mizuna

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Mizuna

5
successive plantings in your 139-day season

Sow every 3.4 weeks. Last sowing by Aug 15 to harvest before frost.

For a dedicated fall crop, sow by Jul 21.

Plant Water Budget

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

Monthly Watering Guide for Mizuna

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

Month Mizuna 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 4.3" 1.4" 2.9" 🚿 Regular watering
Jun 4.3" 2.4" 1.9" 💧 Light watering
Jul 4.3" 3.2" 1.1" 💧 Light watering
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 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.

Mizuna 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.

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

Mizuna Planting Timeline — Kodiak Island Borough, AK

Mizuna Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 13 May 13 – May 27
Direct Sow April 29 Apr 29 – May 20
Harvest June 17 Jun 17 – Jul 15
Fall Sowing July 21 Jul 21 – Aug 4

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

30–45 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 Mizuna in Kodiak Island Borough

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

Your generous 139.0-day season in Kodiak Island Borough allows multiple plantings of Mizuna. Sow every 15.0 days for continuous harvest.

Common pests for Mizuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

Kodiak Island Borough is in Zone 7b with an average last frost of May 13. Plan your Mizuna 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.

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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 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.