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When to plant Cauliflower in Flathead County, MT

Flathead County's climate puts the Cauliflower spring window between May 20 and June 10. time plantings around the expected last-frost window for best survival. A second sowing from July 2 to July 16 extends the harvest into fall.

When to Plant Cauliflower in Flathead County, MT

Cauliflower

Cauliflower is a cool-season brassica that produces dense white, purple, or green heads called curds. It is more finicky than broccoli but rewards with a mild, nutty flavor.

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 Cauliflower during the growing season.

Flathead County, MT (Zone 5a) Very short season
99 days
Last Spring Frost June 3
99 growing days
First Fall Frost September 10

Flathead County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

How Much Cauliflower to Grow

1-2 lbs
Average yield per plant
3
Plants per person
6 sq ft
Space per person

For a family of 4, plant approximately 12 cauliflower plants in about 24 sq ft. In Flathead County's 99-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Cauliflower Planting Timeline — Flathead County, MT

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors April 29 Apr 29 – May 13
Transplant Outdoors June 3 Jun 3 – Jun 17
Direct Sow May 20 May 20 – Jun 10
Harvest July 29 Jul 29 – Sep 30
Fall Sowing July 2 Jul 2 – Jul 16

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

High — keep soil consistently moist

📅 Days to Maturity

55–100 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 6 weeks before transplanting. Blanch white varieties by tying outer leaves over the head. Provide consistent moisture and avoid temperature extremes.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cauliflower in Flathead County, MT?

Flathead County is in Zone 5a with an average last frost of June 3. Plan your Cauliflower 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 Cauliflower in Flathead County, MT?

In Flathead County, MT, plant Cauliflower 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, MT for Cauliflower?

Flathead County sits in USDA Zone 5a. Cauliflower grows reliably in zones 2a through 10b, so it's a good fit here.

Can Cauliflower grow in Flathead County's climate?

Yes — Cauliflower grows well in Flathead County's temperate climate. Flathead 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.

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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 Flathead County, MT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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