When to Plant Broccoli in Slope County, ND
May in the garden — Slope County, North Dakota
Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.
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Move broccoli into the garden
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
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Sow broccoli where they'll grow
Mark the row. Birds and stray feet both have opinions about unmarked beds.
Before June arrives, get these ready
- Starting indoors: broccoli
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.
Slope County, North Dakota is in USDA Zone 4b. The average last spring frost is May 15 and the first fall frost is September 24, giving you a growing season of approximately 132 days.
At an elevation of 1,230 feet, Slope County receives approximately 31.4 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.
Slope County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.6
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.
Soil Compatibility in Slope County
How your county's soil matches Broccoli's growing requirements.
Soil pH
Your soil pH (6.7–7.6) is more alkaline than Broccoli prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Slope County is excellent for Broccoli — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Broccoli.
Organic Matter
Organic matter is excellent (4.2%) — Broccoli will thrive.
How to Plant Broccoli
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Broccoli
Sow every 6.9 weeks. Last sowing by Jun 26 to harvest before frost.
For a dedicated fall crop, sow by Jul 02.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Broccoli
Broccoli needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Broccoli Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.4" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | — | 3.1" | 0" | ❄️ Dormant |
| Apr | — | 2.9" | 0" | ❄️ Dormant |
| May | 4.3" | 3.3" | 1" | 💧 Light watering |
| Jun | 4.3" | 2.3" | 2" | 💧 Light watering |
| Jul | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Aug | 4.3" | 3" | 1.3" | 💧 Light watering |
| Sep | 4.3" | 2.3" | 2" | 💧 Light watering |
| Oct | — | 2.7" | 0" | ❄️ Dormant |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Slope County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Broccoli 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.
Broccoli Planting Timeline — Slope County, ND
Broccoli Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 3 | Apr 3 – Apr 17 |
| Transplant Outdoors | May 15 | May 15 – May 29 |
| Direct Sow | May 8 | May 8 – May 29 |
| Harvest | July 17 | Jul 17 – Aug 28 |
| Fall Sowing | July 2 | Jul 2 – Jul 16 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| 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
1"/week · 1-2 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 4b
📆 Growing Season
132 days in Slope County
Growing Tips for Broccoli in Slope County
Direct sow Broccoli outdoors after May 15 in Slope County when soil has warmed and frost danger has passed.
Common pests for Broccoli in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.
Broccoli in Other Locations
Frequently Asked Questions
When should I plant Broccoli in Slope County, ND?
Slope County is in Zone 4b with an average last frost of May 15. Plan your Broccoli planting based on this frost date — see the calendar above for exact timing.
What planting zone is Slope County, ND?
Slope County, North Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 15 and first fall frost is September 24.
Your Slope County Garden Planner — Free
A 24-page printable planner built for Slope County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.