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When to Plant Soybeans in Anchorage Municipality, AK

Anchorage Municipality, Alaska Zone 5a May

Your May gardening checklist

We've pulled the most time-sensitive tasks for Anchorage Municipality, Alaska this May and put them front and centre. Tackle them in order.

Avg. last frost May 15
Avg. first frost September 19
Soil temp (4") 46°F
Watering Critical
Pest pressure Low
Daylight 17.1 hrs
  1. Direct-sow soybeans

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

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Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.

Anchorage Municipality, Alaska is in USDA Zone 5a. The average last spring frost is May 15 and the first fall frost is September 19, giving you a growing season of approximately 127 days.

At an elevation of 2,537 feet, Anchorage Municipality receives approximately 20.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 71°F, so choose short-season varieties of Soybeans to ensure they mature before fall.

Anchorage Municipality, AK (Zone 5a) Short season
127 days
Last Spring Frost May 15
127 growing days
First Fall Frost September 19

Anchorage Municipality Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 4 🍅 Harvest: Jul 27 – Sep 21
Recommended (50%) ✗ May not fit
Transplant: May 15 🍅 Harvest: Aug 7 – Oct 2
Safe Start (90%) ✗ May not fit
Transplant: Jun 2 🍅 Harvest: Aug 25 – Oct 20

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 Anchorage Municipality

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

Soil pH

Your soil pH (4.9–6.5) is more acidic than Soybeans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Anchorage Municipality is excellent for Soybeans — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Soybeans.

Organic Matter

Organic matter is excellent (5.2%) — Soybeans will thrive.

How to Plant Soybeans

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 29 gal / 100 sq ft

Monthly Watering Guide for Soybeans

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

Month Soybeans Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 0.8" 0" ❄️ Dormant
Apr 0.6" 0" ❄️ Dormant
May 4.3" 0.9" 3.4" 🚿 Regular watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2.6" 1.7" 💧 Light watering
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 2.4" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Anchorage Municipality). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Soybeans 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.

Soybeans needs ~325 GDD — county provides 412 GDD Good fit

Soybeans Planting Timeline — Anchorage Municipality, AK

Soybeans Planting Calendar

Activity When Date Range
Direct Sow May 22 May 22 – Jun 12
Harvest August 14 Aug 14 – Oct 9

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June Direct Sow
July
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

127 days in Anchorage Municipality

Growing Tips for Soybeans in Anchorage Municipality

Direct sow Soybeans outdoors after May 15 in Anchorage Municipality when soil has warmed and frost danger has passed.

Your 127.0-day growing season in Anchorage Municipality is tight for Soybeans (80.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Soybeans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

Anchorage Municipality receives only 20" of rain annually. Soybeans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in Anchorage Municipality, AK?

Anchorage Municipality is in Zone 5a with an average last frost of May 15. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Anchorage Municipality, AK?

Anchorage Municipality, Alaska is in USDA Hardiness Zone 5a. The average last spring frost is May 15 and first fall frost is September 19.

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Your Anchorage Municipality Garden Planner — Free

A 24-page printable planner built for Anchorage Municipality (Zone 5a). 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 Anchorage Municipality, 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.