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When to Plant Napa Cabbage in Yukon-Koyukuk Census Area, AK

Yukon-Koyukuk Census Area, Alaska Zone 2a May

What to do in May

Welcome to May in Zone 2a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 29
Avg. first frost August 26
Soil temp (4") 43°F
Watering High
Pest pressure Low
Daylight 18.5 hrs
  1. Transplant napa cabbage outside

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Plant napa cabbage from seed, right in the garden

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

Coming up in June — start thinking about
  • Fall sowing: napa cabbage

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Napa cabbage forms tall, barrel-shaped heads with tender, crinkled leaves and a mild, slightly sweet flavor. It is the primary cabbage used for kimchi.

Yukon-Koyukuk Census Area, Alaska is in USDA Zone 2a. The average last spring frost is May 29 and the first fall frost is August 26, giving you a growing season of approximately 89 days.

At an elevation of 2,163 feet, Yukon-Koyukuk Census Area receives approximately 55.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 69°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Napa Cabbage root diseases.

Yukon-Koyukuk Census Area, AK (Zone 2a) Very short season
89 days
Last Spring Frost May 29
89 growing days
First Fall Frost August 26
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Yukon-Koyukuk Census Area Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 9 Transplant: May 21 🍅 Harvest: Jul 16 – Aug 20
Recommended (50%) ✗ May not fit
Start indoors: Apr 17 Transplant: May 29 🍅 Harvest: Jul 24 – Aug 28
Safe Start (90%) ✗ May not fit
Start indoors: May 1 Transplant: Jun 12 🍅 Harvest: Aug 7 – Sep 11

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 Yukon-Koyukuk Census Area

How your county's soil matches Napa Cabbage's growing requirements.

Soil pH

Your soil pH (5.0–6.5) is more acidic than Napa Cabbage prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Yukon-Koyukuk Census Area is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Napa Cabbage.

Organic Matter

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

How to Plant Napa Cabbage

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Plant Water Budget

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

Monthly Watering Guide for Napa Cabbage

Napa Cabbage needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Napa Cabbage Needs Rainfall You Supplement Action
Jan 2.8" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 1.8" 0" ❄️ Dormant
May 6.5" 2.4" 4.1" 🚿 Regular watering
Jun 6.5" 3.7" 2.8" 💧 Light watering
Jul 6.5" 6.8" 0" ✅ Rainfall sufficient
Aug 6.5" 7.8" 0" ✅ Rainfall sufficient
Sep 9.3" 0" ❄️ Dormant
Oct 8.2" 0" ❄️ Dormant
Nov 4.3" 0" ❄️ Dormant
Dec 4.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Aug in Yukon-Koyukuk Census Area). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Napa Cabbage 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.

Napa Cabbage needs ~114 GDD — county provides 155 GDD Excellent fit

Napa Cabbage Planting Timeline — Yukon-Koyukuk Census Area, AK

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 17 Apr 17 – May 1
Transplant Outdoors May 29 May 29 – Jun 12
Direct Sow May 22 May 22 – Jun 12
Harvest July 24 Jul 24 – Aug 28
Fall Sowing June 3 Jun 3 – Jun 17

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · Natural rainfall sufficient

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 2a

📆 Growing Season

89 days in Yukon-Koyukuk Census Area

Growing Tips for Napa Cabbage in Yukon-Koyukuk Census Area

Direct sow Napa Cabbage outdoors after May 29 in Yukon-Koyukuk Census Area when soil has warmed and frost danger has passed.

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

General growing tips

Best grown as a fall crop. Direct sow in late summer, 60-70 days before first frost. Keep soil evenly moist. Bolt-resistant varieties are available for spring planting.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Napa Cabbage in Yukon-Koyukuk Census Area, AK?

Yukon-Koyukuk Census Area is in Zone 2a with an average last frost of May 29. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yukon-Koyukuk Census Area, AK?

Yukon-Koyukuk Census Area, Alaska is in USDA Hardiness Zone 2a. The average last spring frost is May 29 and first fall frost is August 26.

🌱

Your Yukon-Koyukuk Census Area Garden Planner — Free

A 24-page printable planner built for Yukon-Koyukuk Census Area (Zone 2a). 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 Yukon-Koyukuk 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.