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When to Plant Borage in Powell 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.

Powell County, Montana is in USDA Zone 4a. The average last spring frost is June 6 and the first fall frost is September 8, giving you a growing season of approximately 94 days.

At an elevation of 5,514 feet, Powell County receives approximately 22.9 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Borage to ensure they mature before fall.

Powell County, MT (Zone 4a) Very short season
94 days
Last Spring Frost June 6
94 growing days
First Fall Frost September 8

Powell County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 8 – Aug 26
Recommended (50%) ✗ May not fit
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Jul 25 – Sep 12
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: May 9 Transplant: Jun 13 🍅 Harvest: Aug 8 – Sep 26

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
1.0″/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 ~715 GDD — county provides 1,222 GDD Excellent fit

Borage Planting Timeline โ€” Powell County, MT

Borage Planting Calendar

Activity When Date Range
Start Indoors April 25 Apr 25 โ€“ May 9
Transplant Outdoors May 30 May 30 โ€“ Jun 13
Direct Sow May 30 May 30 โ€“ Jun 20
Fall Sowing June 16 Jun 16 โ€“ Jun 30
Harvest July 25 Jul 25 โ€“ Sep 12

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 Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow Fall Sowing
July 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 Powell 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 Powell County, MT?

Powell County is in Zone 4a with an average last frost of June 6. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Powell County, MT?

Powell County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is June 6 and first fall frost is September 8.

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Plan Your Garden with Confidence

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