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When to plant Cauliflower in Fremont County, ID

The best window to plant Cauliflower in Fremont County, is May 29–June 19, when soil warms to 50°F. Last frost typically hits June 12; first frost September 6. A second sowing from June 28 to July 12 extends the harvest into fall.

When to Plant Cauliflower in Fremont County, ID

Cauliflower
Fremont County, Idaho Zone 5a June

What to do in June

Here's what deserves your attention in Fremont County, Idaho this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost June 12
Avg. first frost September 6
Soil temp (4") 52°F
Watering Critical
Pest pressure High
Daylight 15.3 hrs
  1. Move cauliflower into the garden

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Direct-sow cauliflower for cool weather

    Keep young seedlings shaded and moist in summer heat. A row of taller crops works as natural shade.

July will be here before you know it — start on
  • Starting indoors: cauliflower

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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.

Fremont County, Idaho is in USDA Zone 5a. The average last spring frost is June 12 and the first fall frost is September 6, giving you a growing season of approximately 86 days.

At an elevation of 5,282 feet, Fremont County receives approximately 12.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Cauliflower to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Cauliflower successfully. Mulch heavily to conserve soil moisture.

Fremont County, ID (Zone 5a) Very short season
86 days
Last Spring Frost June 12
86 growing days
First Fall Frost September 6

Fremont County Soil Profile

Soil Type

Loam

Soil pH

6.4-8

Drainage

Well Drained

Cauliflower Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 18 Transplant: May 23 🍅 Harvest: Jul 18 – Sep 19
Recommended (50%) ✗ May not fit
Start indoors: May 8 Transplant: Jun 12 🍅 Harvest: Aug 7 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: May 23 Transplant: Jun 27 🍅 Harvest: Aug 22 – Oct 24

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.

Soil Compatibility in Fremont County

How your county's soil matches Cauliflower's growing requirements.

Soil pH

Your soil pH (6.4–8.0) is more alkaline than Cauliflower prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Fremont County is excellent for Cauliflower — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Cauliflower.

How to Plant Cauliflower

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

How Much Cauliflower to Grow

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

For a family of 4, plant approximately 12 cauliflower plants in about 30 sq ft. In Fremont County's 86-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Cauliflower Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 349 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 0.8" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 1.6" 0" ❄️ Dormant
Jun 4.3" 1" 3.3" 🚿 Regular watering
Jul 4.3" 1" 3.3" 🚿 Regular watering
Aug 4.3" 1.5" 2.8" 🚿 Regular watering
Sep 4.3" 1" 3.3" 🚿 Regular watering
Oct 1" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Cauliflower Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Cauliflower needs ~1,008 GDD — county provides 1,118 GDD Good fit

Cauliflower Planting Timeline — Fremont County, ID

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors May 8 May 8 – May 22
Transplant Outdoors June 12 Jun 12 – Jun 26
Direct Sow May 29 May 29 – Jun 19
Harvest August 7 Aug 7 – Oct 9
Fall Sowing June 28 Jun 28 – Jul 12

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

55–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

86 days in Fremont County

Growing Tips for Cauliflower in Fremont County

Direct sow Cauliflower outdoors after June 12 in Fremont County when soil has warmed and frost danger has passed.

Your 86.0-day growing season in Fremont County is tight for Cauliflower (55.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Cauliflower in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Fremont County receives only 13" of rain annually. Cauliflower needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

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 Fremont County, ID?

Fremont County is in Zone 5a with an average last frost of June 12. Plan your Cauliflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fremont County, ID?

Fremont County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is June 12 and first fall frost is September 6.

When should I plant Cauliflower in Fremont County, ID?

In Fremont County, ID, plant Cauliflower after the last frost (around June 12) and before the first frost (around September 6). Best results when soil holds above 50°F.

What growing zone is Fremont County, ID for Cauliflower?

Fremont 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 Fremont County's climate?

Yes — Cauliflower grows well in Fremont County's temperate climate. Fremont County averages a 86-day frost-free season, with last frost around June 12 and first frost around September 6.

🌱

Your Fremont County Garden Planner — Free

A 22-page printable planner built for Fremont 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 Fremont County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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