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When to Plant Broccoli Rabe in Oconto County, WI

Oconto County, Wisconsin Zone 5a May

Your May gardening checklist

May is a pivotal month for Oconto County, Wisconsin gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 9
Avg. first frost October 4
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Harden off and plant broccoli rabe

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

Looking ahead to June
  • Starting indoors: broccoli rabe
  • First harvests: broccoli rabe

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Broccoli rabe (rapini) is a brassica grown for its slightly bitter, nutty-flavored florets, leaves, and stems. It is a staple in Italian cooking.

Oconto County, Wisconsin is in USDA Zone 5a. The average last spring frost is May 9 and the first fall frost is October 4, giving you a growing season of approximately 148 days.

At an elevation of 794 feet, Oconto County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Broccoli Rabe to ensure they mature before fall.

Oconto County, WI (Zone 5a) Short season
148 days
Last Spring Frost May 9
148 growing days
First Fall Frost October 4
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Oconto County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (72 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Jun 14 – Jul 19
Recommended (50%) ✓ Fits season (71 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jun 20 – Jul 25
Safe Start (90%) ✓ Fits season (70 days to spare)
Start indoors: Apr 21 Transplant: May 26 🍅 Harvest: Jul 7 – Aug 11

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 Oconto County

How your county's soil matches Broccoli Rabe's growing requirements.

Soil pH

Your soil pH (6.0–7.0) is within Broccoli Rabe's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Oconto 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

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Broccoli Rabe

4
successive plantings in your 148-day season

Sow every 4.6 weeks. Last sowing by Aug 05 to harvest before frost.

For a dedicated fall crop, sow by Jul 26.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 3.5" 4.1" 0" ✅ Rainfall sufficient
Jun 3.5" 4.7" 0" ✅ Rainfall sufficient
Jul 3.5" 4.6" 0" ✅ Rainfall sufficient
Aug 3.5" 4.1" 0" ✅ Rainfall sufficient
Sep 3.5" 3.3" 0.2" 💧 Light watering
Oct 3.5" 2.7" 0.8" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Oconto 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 needs ~500 GDD — county provides 1,480 GDD Excellent fit

Broccoli Rabe Planting Timeline — Oconto County, WI

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 – Apr 18
Transplant Outdoors May 9 May 9 – May 23
Direct Sow April 25 Apr 25 – May 16
Harvest June 20 Jun 20 – Jul 25
Fall Sowing July 26 Jul 26 – Aug 9

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5a

📆 Growing Season

148 days in Oconto County

Growing Tips for Broccoli Rabe in Oconto County

Direct sow Broccoli Rabe outdoors after May 09 in Oconto 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

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

Oconto County is in Zone 5a with an average last frost of May 9. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Oconto County, WI?

Oconto County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is May 9 and first fall frost is October 4.

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Your Oconto County Garden Planner — Free

A 24-page printable planner built for Oconto County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Oconto County, WI. Local conditions may vary. Last updated: May 2026.

Sources & credits

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