When to Plant Cauliflower in Boundary 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.
Boundary County, Idaho is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is September 22, giving you a growing season of approximately 135 days.
At an elevation of 5,105 feet, Boundary County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Cauliflower during the growing season.
Boundary County Soil Profile
Soil Type
Loam
Soil pH
6.7-8.3
Drainage
Well Drained
Plant Planting Risk Windows
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.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Cauliflower Planting Timeline — Boundary County, ID
Cauliflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Direct Sow | April 26 | Apr 26 – May 17 |
| Fall Sowing | July 14 | Jul 14 – Jul 28 |
| Harvest | July 5 | Jul 5 – Sep 6 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| 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
6 – 7
USDA Zone
Zone 5b
Growing Season
135 days
Growing Tips for Boundary 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
Level Up Your Garden
Cauliflower in Other Locations
Frequently Asked Questions
When should I plant Cauliflower in Boundary County, ID?
Boundary County is in Zone 5b with an average last frost of May 10. Plan your Cauliflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Boundary County, ID?
Boundary County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is September 22.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Boundary County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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