When to Plant Borage in Carbon 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.
Carbon County, Montana is in USDA Zone 4b. The average last spring frost is May 13 and the first fall frost is September 28, giving you a growing season of approximately 138 days.
At an elevation of 5,849 feet, Carbon County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Borage to ensure they mature before fall.
Carbon County Soil Profile
Soil Type
Loam
Soil pH
6.8-8.1
Drainage
Well Drained
Plant Planting Risk Windows
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
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Borage Planting Timeline — Carbon County, MT
Borage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 1 | Apr 1 – Apr 15 |
| Transplant Outdoors | May 6 | May 6 – May 20 |
| Direct Sow | May 6 | May 6 – May 27 |
| Fall Sowing | July 6 | Jul 6 – Jul 20 |
| Harvest | July 1 | Jul 1 – Aug 19 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Low — drought tolerant
Days to Maturity
50–60 days
Soil pH
6 – 7
USDA Zone
Zone 4b
Growing Season
138 days
Growing Tips for Carbon 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
Borage in Other Locations
Frequently Asked Questions
When should I plant Borage in Carbon County, MT?
Carbon County is in Zone 4b with an average last frost of May 13. Plan your Borage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Carbon County, MT?
Carbon County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 13 and first fall frost is September 28.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Carbon County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.