When to Plant Broccoli in Yellowstone County, MT
Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.
Yellowstone County, Montana is in USDA Zone 4b. The average last spring frost is May 9 and the first fall frost is October 3, giving you a growing season of approximately 147 days.
At an elevation of 7,432 feet, Yellowstone County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Broccoli to ensure they mature before fall.
Yellowstone County Soil Profile
Soil Type
Loam
Soil pH
6.2-8
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 8/10 — consider drought-tolerant varieties and mulching
Broccoli Planting Timeline — Yellowstone County, MT
Broccoli Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 28 | Mar 28 – Apr 11 |
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Direct Sow | May 2 | May 2 – May 23 |
| Fall Sowing | July 11 | Jul 11 – Jul 25 |
| Harvest | July 11 | Jul 11 – Aug 22 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
60–90 days
Soil pH
6 – 7
USDA Zone
Zone 4b
Growing Season
147 days
Growing Tips for Yellowstone County
Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.
Broccoli in Other Locations
Frequently Asked Questions
When should I plant Broccoli in Yellowstone County, MT?
Yellowstone County is in Zone 4b with an average last frost of May 9. Plan your Broccoli planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yellowstone County, MT?
Yellowstone County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 9 and first fall frost is October 3.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Yellowstone County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.