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When to Plant Mitsuba in Kodiak Island Borough, AK

Kodiak Island Borough, Alaska Zone 6a April

Your April game plan for Kodiak Island Borough, Alaska

Here's what deserves your attention in Kodiak Island Borough, Alaska this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost May 13
Avg. first frost September 29
Soil temp (4") 43°F
Watering Critical
Pest pressure Low
Daylight 14 hrs
  1. Seed mitsuba outdoors

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

Get ahead of May
  • Transplants going out: mitsuba

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Mitsuba (Japanese parsley) is a shade-loving herb with trefoil leaves and a mild celery-parsley flavor. It is essential in Japanese cuisine for soups, salads, and garnishes.

Kodiak Island Borough, Alaska is in USDA Zone 6a. 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 Mitsuba to ensure they mature before fall.

Kodiak Island Borough, AK (Zone 6a) Short season
139 days
Last Spring Frost May 13
139 growing days
First Fall Frost September 29
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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 (42 days to spare)
Start indoors: Mar 28 Transplant: Apr 25 🍅 Harvest: Jun 20 – Aug 15
Recommended (50%) ✓ Fits season (34 days to spare)
Start indoors: Apr 8 Transplant: May 6 🍅 Harvest: Jul 1 – Aug 26
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Apr 20 Transplant: May 18 🍅 Harvest: Jul 13 – Sep 7

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 Mitsuba's growing requirements.

Soil pH

Your soil pH (5.1–6.5) is more acidic than Mitsuba prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Mitsuba.

Organic Matter

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

How to Plant Mitsuba

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

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

Succession Planting Mitsuba

3
successive plantings in your 139-day season

Sow every 5.7 weeks. Last sowing by Jul 21 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 Mitsuba

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

Month Mitsuba 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.

Mitsuba 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.

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

Mitsuba Planting Timeline — Kodiak Island Borough, AK

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest July 1 Jul 1 – Aug 26
Fall Sowing July 21 Jul 21 – Aug 4

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6a

📆 Growing Season

139 days in Kodiak Island Borough

Growing Tips for Mitsuba in Kodiak Island Borough

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

Common pests for Mitsuba in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow or start indoors in partial shade. Mitsuba prefers cool, moist conditions. Harvest outer stems as needed. Self-sows readily in shaded garden areas.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

Kodiak Island Borough is in Zone 6a with an average last frost of May 13. Plan your Mitsuba 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 6a. The average last spring frost is May 13 and first fall frost is September 29.

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Your Kodiak Island Borough Garden Planner — Free

A 24-page printable planner built for Kodiak Island Borough (Zone 6a). 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: April 2026.

Sources & credits

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