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When to Plant Borage in Beaverhead County, MT

Borage is a self-seeding annual herb with star-shaped blue flowers that attract pollinators. Its leaves have a cucumber-like flavor and the flowers are edible.

Beaverhead County, Montana is in USDA Zone 4a. The average last spring frost is June 10 and the first fall frost is September 12, giving you a growing season of approximately 94 days.

At an elevation of 7,645 feet, Beaverhead County receives approximately 15.7 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Borage to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Borage successfully. Mulch heavily to conserve soil moisture.

Beaverhead County, MT (Zone 4a) Very short season
94 days
Last Spring Frost June 10
94 growing days
First Fall Frost September 12

Beaverhead County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Apr 19 Transplant: May 24 🍅 Harvest: Jul 19 – Sep 6
Recommended (50%) ✗ May not fit
Start indoors: Apr 29 Transplant: Jun 3 🍅 Harvest: Jul 29 – Sep 16
Safe Start (90%) ✓ Fits season (0 days to spare)
Start indoors: May 11 Transplant: Jun 15 🍅 Harvest: Aug 10 – Sep 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
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Borage needs ~550 GDD — county provides 940 GDD Excellent fit

Borage Planting Timeline โ€” Beaverhead County, MT

Borage Planting Calendar

Activity When Date Range
Start Indoors April 29 Apr 29 โ€“ May 13
Transplant Outdoors June 3 Jun 3 โ€“ Jun 17
Direct Sow June 3 Jun 3 โ€“ Jun 24
Fall Sowing June 20 Jun 20 โ€“ Jul 4
Harvest July 29 Jul 29 โ€“ Sep 16

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

50โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4a

Growing Season

94 days

Growing Tips for Beaverhead County

Direct sow in spring as borage does not transplant well. Allow some plants to go to seed for next year. Young leaves are best; older leaves become bristly.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Borage in Beaverhead County, MT?

Beaverhead County is in Zone 4a with an average last frost of June 10. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Beaverhead County, MT?

Beaverhead County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is June 10 and first fall frost is September 12.

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Plan Your Garden with Confidence

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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 Beaverhead County, MT. Local conditions may vary. Last updated: April 2026.