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When to Plant Broccoli Rabe in Jackson 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.

Jackson County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 13 and the first fall frost is October 2, giving you a growing season of approximately 142 days.

At an elevation of 608 feet, Jackson County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Broccoli Rabe to ensure they mature before fall.

Jackson County, WI (Zone 4b) Short season
142 days
Last Spring Frost May 13
142 growing days
First Fall Frost October 2

Jackson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Mar 24 Transplant: May 5 🍅 Harvest: Jun 16 – Jul 21
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Apr 1 Transplant: May 13 🍅 Harvest: Jun 24 – Jul 29
Safe Start (90%) ✓ Fits season (68 days to spare)
Start indoors: Apr 9 Transplant: May 21 🍅 Harvest: Jul 2 – Aug 6

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

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Broccoli Rabe needs ~650 GDD — county provides 1,846 GDD Excellent fit

Broccoli Rabe Planting Timeline โ€” Jackson County, WI

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 โ€“ Apr 15
Transplant Outdoors May 13 May 13 โ€“ May 27
Direct Sow May 6 May 6 โ€“ May 27
Fall Sowing July 10 Jul 10 โ€“ Jul 24
Harvest June 24 Jun 24 โ€“ Jul 29

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

40โ€“60 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4b

Growing Season

142 days

Growing Tips for Jackson County

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

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

When should I plant Broccoli Rabe in Jackson County, WI?

Jackson County is in Zone 4b with an average last frost of May 13. Plan your Broccoli Rabe planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jackson County, WI?

Jackson County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 13 and first fall frost is October 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jackson County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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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 Jackson County, WI. Local conditions may vary. Last updated: April 2026.