When to plant Basil in Flathead County County,
Flathead County County sits in cold Zone 5a. Plant Basil June 10–July 1 for the single annual harvest; the September 10 first frost closes the window.
When to Plant Basil in Flathead 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.
Flathead County, Montana is in USDA Zone 5a. The average last spring frost is June 3 and the first fall frost is September 10, giving you a growing season of approximately 99 days.
At an elevation of 6,233 feet, Flathead County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Basil during the growing season.
Flathead County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.4
Drainage
Well Drained
Monthly Watering Guide for Basil
Basil needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Basil Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 2.2" | 0" | ❄️ Dormant |
| May | — | 2.7" | 0" | ❄️ Dormant |
| Jun | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Jul | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Aug | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Sep | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Oct | — | 1.9" | 0" | ❄️ Dormant |
| Nov | — | 1.6" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Flathead County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Basil Planting Timeline — Flathead County, MT
Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 15 | Apr 15 – Apr 29 |
| Transplant Outdoors | June 17 | Jun 17 – Jul 1 |
| Direct Sow | June 10 | Jun 10 – Jul 1 |
| Harvest | August 12 | Aug 12 – Oct 14 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | — |
| June | Transplant Outdoors Direct Sow |
| July | Transplant Outdoors Direct Sow |
| 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
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5a
📆 Growing Season
99 days in Flathead County
Growing Tips for Flathead 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
Check more plant combinations with our Companion Planting Checker →
Isolate 150 ft between varieties. Different basil species can cross.
Basil in Other Locations
Frequently Asked Questions
When should I plant Basil in Flathead County, MT?
Flathead County is in Zone 5a with an average last frost of June 3. Plan your Basil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Flathead County, MT?
Flathead County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 3 and first fall frost is September 10.
When should I plant Basil in Flathead County County, ?
In Flathead County County, , plant Basil after the last frost (around June 3) and before the first frost (around September 10). Best results when soil holds above 50°F.
What growing zone is Flathead County County, for Basil?
Flathead County County sits in USDA Zone 5a. Basil grows reliably in zones 4a through 11b, so it's a good fit here.
Can Basil grow in Flathead County County's climate?
Yes — Basil grows well in Flathead County County's temperate climate. Flathead County County averages a 99-day frost-free season, with last frost around June 3 and first frost around September 10.
Your Flathead County Garden Planner — Free
A 22-page printable planner built for Flathead County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.