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When to plant Cauliflower in St. Clair County, MI

Spring Cauliflower in St. Clair County goes in April 13–May 4, once nighttime temps stop dipping near freezing. A second sowing from August 18 to September 1 extends the harvest into fall.

When to Plant Cauliflower in St. Clair County, MI

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.

St. Clair County, Michigan is in USDA Zone 6a. The average last spring frost is April 27 and the first fall frost is October 27, giving you a growing season of approximately 183 days.

At an elevation of 1,065 feet, St. Clair County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Cauliflower during the growing season.

St. Clair County, MI (Zone 6a) Moderate season
183 days
Last Spring Frost April 27
183 growing days
First Fall Frost October 27

St. Clair County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.2

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 St. Clair County's 183-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Monthly Watering Guide for Cauliflower

Cauliflower needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Cauliflower Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in St. Clair County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Cauliflower Planting Timeline — St. Clair County, MI

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 13 Apr 13 – May 4
Harvest June 22 Jun 22 – Aug 24
Fall Sowing August 18 Aug 18 – Sep 1

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Fall Sowing Harvest
September Fall Sowing
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 6a

📆 Growing Season

183 days in St. Clair County

Growing Tips for St. Clair 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 St. Clair County, MI?

St. Clair County is in Zone 6a with an average last frost of April 27. Plan your Cauliflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Clair County, MI?

St. Clair County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is April 27 and first fall frost is October 27.

When should I plant Cauliflower in St. Clair County, MI?

In St. Clair County, MI, plant Cauliflower after the last frost (around April 27) and before the first frost (around October 27). Best results when soil holds above 50°F.

What growing zone is St. Clair County, MI for Cauliflower?

St. Clair County sits in USDA Zone 6a. Cauliflower grows reliably in zones 2a through 10b, so it's a good fit here.

Can Cauliflower grow in St. Clair County's climate?

Yes — Cauliflower grows well in St. Clair County's temperate climate. St. Clair County averages a 183-day frost-free season, with last frost around April 27 and first frost around October 27.

🌱

Your St. Clair County Garden Planner — Free

A 22-page printable planner built for St. Clair County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for St. Clair County, MI. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.