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When to Plant Scallions in Bannock County, ID

Scallions (green onions) are mild-flavored alliums harvested for their slender green tops and white bases. They are quick-growing and perfect for succession planting.

Bannock County, Idaho is in USDA Zone 5a. The average last spring frost is May 23 and the first fall frost is September 24, giving you a growing season of approximately 124 days.

At an elevation of 5,637 feet, Bannock County receives approximately 13.1 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Scallions to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Scallions successfully. Mulch heavily to conserve soil moisture.

Bannock County, ID (Zone 5a) Short season
124 days
Last Spring Frost May 23
124 growing days
First Fall Frost September 24

Bannock County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (41 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Jul 5 – Aug 2
Recommended (50%) ✓ Fits season (40 days to spare)
Start indoors: Apr 18 Transplant: May 23 🍅 Harvest: Jul 18 – Aug 15
Safe Start (90%) ✓ Fits season (37 days to spare)
Start indoors: May 14 Transplant: Jun 18 🍅 Harvest: Aug 13 – Sep 10

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 1-2 times/week
Season total 737 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Scallions needs ~735 GDD — county provides 1,519 GDD Excellent fit

Scallions Planting Timeline โ€” Bannock County, ID

Scallions Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 โ€“ May 2
Transplant Outdoors May 23 May 23 โ€“ Jun 6
Direct Sow May 9 May 9 โ€“ May 30
Fall Sowing July 16 Jul 16 โ€“ Jul 30
Harvest July 18 Jul 18 โ€“ Aug 15

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“70 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

124 days

Growing Tips for Bannock County

Direct sow every 3 weeks for continuous harvest. Thin to 1 inch apart or grow in clusters. Harvest when pencil-thick by pulling or cutting at soil level.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

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Frequently Asked Questions

When should I plant Scallions in Bannock County, ID?

Bannock County is in Zone 5a with an average last frost of May 23. Plan your Scallions planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Bannock County, ID?

Bannock County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 23 and first fall frost is September 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Bannock 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 Bannock County, ID. Local conditions may vary. Last updated: April 2026.