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When to Plant Cauliflower in Shoshone County, ID

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.

Shoshone County, Idaho is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is September 26, giving you a growing season of approximately 139 days.

At an elevation of 6,353 feet, Shoshone County receives approximately 14.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, 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.

Shoshone County, ID (Zone 5a) Short season
139 days
Last Spring Frost May 10
139 growing days
First Fall Frost September 26

Shoshone County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Jun 28 – Aug 30
Recommended (50%) ✓ Fits season (20 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Jul 5 – Sep 6
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Apr 30 Transplant: Jun 4 🍅 Harvest: Jul 30 – Oct 1

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 Shoshone County

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

Soil pH

Your soil pH (6.6โ€“7.7) is more alkaline than Cauliflower prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Shoshone County is excellent for Cauliflower โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Cauliflower is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is moderate (2.8%). 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.

Succession Planting Cauliflower

2
successive plantings in your 139-day season

Sow every 6.3 weeks. Last sowing by Jun 18 to harvest before frost.

For a dedicated fall crop, sow by Jul 18.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,297 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” 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 โ€” 1" 0" โ„๏ธ Dormant
Feb โ€” 0.7" 0" โ„๏ธ Dormant
Mar โ€” 1.2" 0" โ„๏ธ Dormant
Apr โ€” 1.3" 0" โ„๏ธ Dormant
May 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Jun 4.3" 0.9" 3.4" ๐Ÿšฟ Regular watering
Jul 4.3" 1.2" 3.1" ๐Ÿšฟ Regular watering
Aug 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering
Sep 4.3" 1.3" 3" ๐Ÿšฟ Regular watering
Oct โ€” 1.2" 0" โ„๏ธ Dormant
Nov โ€” 0.9" 0" โ„๏ธ Dormant
Dec โ€” 0.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Shoshone County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 1,807 GDD Excellent fit

Cauliflower Planting Timeline โ€” Shoshone County, ID

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 โ€“ Apr 19
Transplant Outdoors May 10 May 10 โ€“ May 24
Direct Sow April 26 Apr 26 โ€“ May 17
Harvest July 5 Jul 5 โ€“ Sep 6
Fall Sowing July 18 Jul 18 โ€“ Aug 1

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

55โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

139 days in Shoshone County

Growing Tips for Cauliflower in Shoshone County

Direct sow Cauliflower outdoors after May 10 in Shoshone County when soil has warmed and frost danger has passed.

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

Shoshone County receives only 14" of rain annually. Cauliflower needs consistent moisture โ€” 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 Shoshone County, ID?

Shoshone County is in Zone 5a with an average last frost of May 10. Plan your Cauliflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Shoshone County, ID?

Shoshone County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is September 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Shoshone County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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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 Shoshone County, ID. Local conditions may vary. Last updated: April 2026.