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When to Plant Soybeans in Power County, ID

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.

Power County, Idaho is in USDA Zone 5a. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.

At an elevation of 6,609 feet, Power County receives approximately 14 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Soybeans during the growing season. With low rainfall, drip irrigation is essential for growing Soybeans successfully. Mulch heavily to conserve soil moisture.

Power County, ID (Zone 5a) Short season
142 days
Last Spring Frost May 11
142 growing days
First Fall Frost September 30

Power County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Transplant: May 2 🍅 Harvest: Jul 25 – Sep 19
Recommended (50%) ✓ Fits season (2 days to spare)
Transplant: May 11 🍅 Harvest: Aug 3 – Sep 28
Safe Start (90%) ✗ May not fit
Transplant: Jun 11 🍅 Harvest: Sep 3 – Oct 29

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
0.4″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 889 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Soybeans needs ~1,525 GDD — county provides 2,165 GDD Excellent fit

Soybeans Planting Timeline โ€” Power County, ID

Soybeans Planting Calendar

Activity When Date Range
Direct Sow May 18 May 18 โ€“ Jun 8
Harvest August 10 Aug 10 โ€“ Oct 5

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

80โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

142 days

Growing Tips for Power County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Soybeans in Power County, ID?

Power County is in Zone 5a with an average last frost of May 11. Plan your Soybeans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Power County, ID?

Power County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 11 and first fall frost is September 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Power County gardeners in Zone 5a 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 Power County, ID. Local conditions may vary. Last updated: April 2026.