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When to Plant Mizuna in Bethel Census Area, AK

Bethel Census Area, Alaska Zone 4a May

Top priorities for Bethel Census Area, Alaska gardeners in May

Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 22
Avg. first frost September 21
Soil temp (4") 45°F
Watering High
Pest pressure Low
Daylight 17 hrs
  1. Transplant mizuna outside

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Sow mizuna where they'll grow

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

A few tasks this May that'll pay off in June
  • First harvests: mizuna
  • Fall sowing: 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.

Bethel Census Area, Alaska is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is September 21, giving you a growing season of approximately 122 days.

At an elevation of 1,369 feet, Bethel Census Area receives approximately 50.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 70°F, so choose short-season varieties of Mizuna to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Mizuna root diseases.

Bethel Census Area, AK (Zone 4a) Short season
122 days
Last Spring Frost May 22
122 growing days
First Fall Frost September 21

Bethel Census Area Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Apr 4 Transplant: May 16 🍅 Harvest: Jun 20 – Jul 18
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Jun 26 – Jul 24
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Apr 22 Transplant: Jun 3 🍅 Harvest: Jul 8 – Aug 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 Bethel Census Area

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

Soil pH

Your soil pH (5.2–6.3) is more acidic than Mizuna prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Bethel Census Area is excellent for Mizuna — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Mizuna.

Organic Matter

Organic matter is excellent (5.8%) — Mizuna will thrive.

How to Plant Mizuna

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Mizuna

4
successive plantings in your 122-day season

Sow every 3.4 weeks. Last sowing by Aug 07 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.8″/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 2.6" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 4.3" 1.8" 2.5" 🚿 Regular watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 6.3" 0" ✅ Rainfall sufficient
Aug 4.3" 7.6" 0" ✅ Rainfall sufficient
Sep 4.3" 9.4" 0" ✅ Rainfall sufficient
Oct 6.7" 0" ❄️ Dormant
Nov 4.1" 0" ❄️ Dormant
Dec 2.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Bethel Census Area). 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 ~94 GDD — county provides 305 GDD Excellent fit

Mizuna Planting Timeline — Bethel Census Area, AK

Mizuna Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest June 26 Jun 26 – Jul 24
Fall Sowing June 29 Jun 29 – Jul 13

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow Fall Sowing Harvest
July Fall Sowing Harvest
August
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 4a

📆 Growing Season

122 days in Bethel Census Area

Growing Tips for Mizuna in Bethel Census Area

Direct sow Mizuna outdoors after May 22 in Bethel Census Area when soil has warmed and frost danger has passed.

Your generous 122.0-day season in Bethel Census Area 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 Bethel Census Area, AK?

Bethel Census Area is in Zone 4a with an average last frost of May 22. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bethel Census Area, AK?

Bethel Census Area, Alaska is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is September 21.

🌱

Your Bethel Census Area Garden Planner — Free

A 24-page printable planner built for Bethel Census Area (Zone 4a). 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 Bethel Census Area, 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.