When to Plant Broccoli Rabe in Douglas County, WI
Broccoli rabe (rapini) is a brassica grown for its slightly bitter, nutty-flavored florets, leaves, and stems. It is a staple in Italian cooking.
Douglas County, Wisconsin is in USDA Zone 3b. The average last spring frost is May 16 and the first fall frost is September 28, giving you a growing season of approximately 135 days.
At an elevation of 1,147 feet, Douglas County receives approximately 31.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Broccoli Rabe to ensure they mature before fall.
Douglas County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
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 Douglas County
How your county's soil matches Broccoli Rabe's growing requirements.
Soil pH
Your soil pH (5.9–6.7) overlaps with Broccoli Rabe's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Douglas County is excellent for Broccoli Rabe — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Broccoli Rabe will thrive.
How to Plant Broccoli Rabe
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Broccoli Rabe
Sow every 4.6 weeks. Last sowing by Jul 30 to harvest before frost.
For a dedicated fall crop, sow by Jul 06.
Plant Water Budget
Monthly Watering Guide for Broccoli Rabe
Broccoli Rabe needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.
| Month | Broccoli Rabe Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | — | 3.4" | 0" | ❄️ Dormant |
| May | 3.5" | 3.4" | 0.1" | 💧 Light watering |
| Jun | 3.5" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 3.2" | 0.3" | 💧 Light watering |
| Aug | 3.5" | 3.1" | 0.4" | 💧 Light watering |
| Sep | 3.5" | 2.7" | 0.8" | 💧 Light watering |
| Oct | — | 2.9" | 0" | ❄️ Dormant |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Douglas County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Broccoli Rabe 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 Rabe Planting Timeline — Douglas County, WI
Broccoli Rabe Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 4 | Apr 4 – Apr 18 |
| Transplant Outdoors | May 16 | May 16 – May 30 |
| Direct Sow | May 9 | May 9 – May 30 |
| Harvest | June 27 | Jun 27 – Aug 1 |
| Fall Sowing | July 6 | Jul 6 – Jul 20 |
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 | Harvest |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Natural rainfall sufficient
📅 Days to Maturity
40–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 3b
📆 Growing Season
135 days in Douglas County
Growing Tips for Broccoli Rabe in Douglas County
Direct sow Broccoli Rabe outdoors after May 16 in Douglas County when soil has warmed and frost danger has passed.
Common pests for Broccoli Rabe in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow in spring or fall. Harvest when small yellow flower buds first appear but before they open. Cut the main shoot first to encourage side shoots.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Broccoli Rabe in Other Locations
Frequently Asked Questions
When should I plant Broccoli Rabe in Douglas County, WI?
Douglas County is in Zone 3b with an average last frost of May 16. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.
What planting zone is Douglas County, WI?
Douglas County, Wisconsin is in USDA Hardiness Zone 3b. The average last spring frost is May 16 and first fall frost is September 28.
Plan Your Garden with Confidence
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