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When to Plant Onion in Dillingham Census Area, AK

Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

Dillingham Census Area, Alaska is in USDA Zone 3a. The average last spring frost is May 1 and the first fall frost is September 6, giving you a growing season of approximately 128 days.

At an elevation of 410 feet, Dillingham Census Area receives approximately 54 inches of rainfall annually with predominantly silt loam soil. Summer highs average 60ยฐF, so choose short-season varieties of Onion to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.

Dillingham Census Area, AK (Zone 3a) Short season
128 days
Last Spring Frost May 1
128 growing days
First Fall Frost September 6

Dillingham Census Area Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (57 days to spare)
Start indoors: Mar 4 Transplant: Apr 15 🍅 Harvest: Jul 15 – Aug 19
Recommended (50%) ✓ Fits season (57 days to spare)
Start indoors: Mar 4 Transplant: Apr 15 🍅 Harvest: Jul 15 – Aug 19
Safe Start (90%) ✓ Fits season (57 days to spare)
Start indoors: Mar 4 Transplant: Apr 15 🍅 Harvest: Jul 15 – Aug 19

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.

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

Onion Planting Timeline โ€” Dillingham Census Area, AK

Onion Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 โ€“ Apr 3
Transplant Outdoors May 1 May 1 โ€“ May 15
Direct Sow April 24 Apr 24 โ€“ May 15
Fall Sowing June 14 Jun 14 โ€“ Jun 28
Harvest July 31 Jul 31 โ€“ Sep 4

Plant 1" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 3a

Growing Season

128 days

Growing Tips for Dillingham Census Area

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Level Up Your Garden

Frequently Asked Questions

When should I plant Onion in Dillingham Census Area, AK?

Dillingham Census Area is in Zone 3a with an average last frost of May 1. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Dillingham Census Area, AK?

Dillingham Census Area, Alaska is in USDA Hardiness Zone 3a. The average last spring frost is May 1 and first fall frost is September 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Dillingham Census Area gardeners in Zone 3a organize planting dates, track what's growing, and never miss a planting window.

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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 Dillingham Census Area, AK. Local conditions may vary. Last updated: April 2026.