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When to Plant Shallot in Stillwater County, MT

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.

Stillwater County, Montana is in USDA Zone 4b. The average last spring frost is May 22 and the first fall frost is September 22, giving you a growing season of approximately 123 days.

At an elevation of 6,319 feet, Stillwater County receives approximately 16.6 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Shallot to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Shallot successfully. Mulch heavily to conserve soil moisture.

Stillwater County, MT (Zone 4b) Short season
123 days
Last Spring Frost May 22
123 growing days
First Fall Frost September 22

Stillwater County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Aug 11 – Sep 29
Recommended (50%) ✗ May not fit
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Aug 21 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: Apr 29 Transplant: Jun 10 🍅 Harvest: Sep 9 – Oct 28

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
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 569 gal / 100 sq ft
Drought risk

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

Shallot needs ~1,286 GDD — county provides 1,506 GDD Good fit

Shallot Planting Timeline โ€” Stillwater County, MT

Shallot Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 โ€“ Apr 24
Transplant Outdoors May 22 May 22 โ€“ Jun 5
Direct Sow May 15 May 15 โ€“ Jun 5
Fall Sowing June 30 Jun 30 โ€“ Jul 14
Harvest August 21 Aug 21 โ€“ Oct 9

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 Direct Sow Fall Sowing
July Fall Sowing
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

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4b

Growing Season

123 days

Growing Tips for Stillwater County

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

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Frequently Asked Questions

When should I plant Shallot in Stillwater County, MT?

Stillwater County is in Zone 4b with an average last frost of May 22. Plan your Shallot planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Stillwater County, MT?

Stillwater County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 22 and first fall frost is September 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Stillwater County gardeners in Zone 4b 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 Stillwater County, MT. Local conditions may vary. Last updated: April 2026.