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When to Plant Shallot in Franklin County, ID

Shallots are a gourmet allium prized for their complex, sweet, and mild flavor. Each bulb multiplies into a cluster, making them easy and rewarding to grow.

Franklin County, Idaho is in USDA Zone 5a. The average last spring frost is May 19 and the first fall frost is October 3, giving you a growing season of approximately 137 days.

At an elevation of 7,665 feet, Franklin County receives approximately 18.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Shallot during the growing season. With low rainfall, drip irrigation is essential for growing Shallot successfully. Mulch heavily to conserve soil moisture.

Franklin County, ID (Zone 5a) Short season
137 days
Last Spring Frost May 19
137 growing days
First Fall Frost October 3

Franklin County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Aug 5 – Sep 23
Recommended (50%) ✗ May not fit
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Aug 18 – Oct 6
Safe Start (90%) ✗ May not fit
Start indoors: May 9 Transplant: Jun 13 🍅 Harvest: Sep 12 – Oct 31

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 Franklin County

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

Soil pH

Your soil pH (6.7โ€“7.7) is more alkaline than Shallot prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Franklin County is excellent for Shallot โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Shallot.

How to Plant Shallot

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 633 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Shallot

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

Month Shallot Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.1" 0" โ„๏ธ Dormant
Mar โ€” 1.5" 0" โ„๏ธ Dormant
Apr โ€” 2" 0" โ„๏ธ Dormant
May 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Jun 4.3" 1.3" 3" ๐Ÿšฟ Regular watering
Jul 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Aug 4.3" 2" 2.3" ๐Ÿšฟ Regular watering
Sep 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Oct 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Nov โ€” 1.2" 0" โ„๏ธ Dormant
Dec โ€” 1.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Franklin County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Shallot 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" โ€” every day above 50ยฐF 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.

Shallot needs ~1,601 GDD — county provides 2,089 GDD Excellent fit

Shallot Planting Timeline โ€” Franklin County, ID

Shallot Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 โ€“ Apr 28
Transplant Outdoors May 19 May 19 โ€“ Jun 2
Direct Sow May 5 May 5 โ€“ May 26
Harvest August 18 Aug 18 โ€“ Oct 6
Fall Sowing July 25 Jul 25 โ€“ Aug 8

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

137 days in Franklin County

Growing Tips for Shallot in Franklin County

Direct sow Shallot outdoors after May 19 in Franklin County when soil has warmed and frost danger has passed.

Common pests for Shallot in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

Franklin County receives only 18" of rain annually. Shallot needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant sets in fall for spring harvest or early spring for summer harvest. Mulch heavily if overwintering. Harvest when tops brown and dry, then cure for storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Shallot in Franklin County, ID?

Franklin County is in Zone 5a with an average last frost of May 19. Plan your Shallot planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Franklin County, ID?

Franklin County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 19 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Franklin County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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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 Franklin County, ID. Local conditions may vary. Last updated: April 2026.