When to Plant Basil in Fallon County, MT
Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.
Fallon County, Montana is in USDA Zone 4a. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.
At an elevation of 6,441 feet, Fallon County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Basil to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Basil successfully. Mulch heavily to conserve soil moisture.
Fallon County Soil Profile
Soil Type
Loam
Soil pH
6.2-8.3
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 6/10 — consider drought-tolerant varieties and mulching
Basil Planting Timeline — Fallon County, MT
Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 25 | Mar 25 – Apr 8 |
| Transplant Outdoors | June 10 | Jun 10 – Jun 24 |
| Direct Sow | May 27 | May 27 – Jun 17 |
| Harvest | August 5 | Aug 5 – Oct 7 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
50–75 days
Soil pH
6 – 7
USDA Zone
Zone 4a
Growing Season
123 days
Growing Tips for Fallon County
Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Isolate 150 ft between varieties. Different basil species can cross.
Basil in Other Locations
Frequently Asked Questions
When should I plant Basil in Fallon County, MT?
Fallon County is in Zone 4a with an average last frost of May 20. Plan your Basil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Fallon County, MT?
Fallon County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 20 and first fall frost is September 20.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Fallon County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
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