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When to Plant Broccoli Rabe in Carbon County, WY

Carbon County, Wyoming Zone 5a May

This month in Carbon County, Wyoming

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 31
Avg. first frost September 18
Soil temp (4") 30°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Set out broccoli rabe seedlings

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

  2. Put broccoli rabe seeds straight in the ground

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

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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.

Carbon County, Wyoming is in USDA Zone 5a. The average last spring frost is May 31 and the first fall frost is September 18, giving you a growing season of approximately 110 days.

At an elevation of 8,469 feet, Carbon County receives approximately 15.2 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Broccoli Rabe to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Broccoli Rabe successfully. Mulch heavily to conserve soil moisture.

Carbon County, WY (Zone 5a) Short season
110 days
Last Spring Frost May 31
110 growing days
First Fall Frost September 18

Carbon County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Apr 21 Transplant: May 26 🍅 Harvest: Jul 7 – Aug 11
Recommended (50%) ✓ Fits season (33 days to spare)
Start indoors: Apr 26 Transplant: May 31 🍅 Harvest: Jul 12 – Aug 16
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: May 8 Transplant: Jun 12 🍅 Harvest: Jul 24 – Aug 28

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 Carbon County

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

Soil pH

Your soil pH (6.7–8.3) overlaps with Broccoli Rabe's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Carbon County is excellent for Broccoli Rabe — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Broccoli Rabe.

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

3
successive plantings in your 110-day season

Sow every 4.6 weeks. Last sowing by Jul 20 to harvest before frost.

For a dedicated fall crop, sow by Jul 10.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.6″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 258 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.2" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 3.5" 2" 1.5" 💧 Light watering
Jun 3.5" 1.1" 2.4" 🚿 Regular watering
Jul 3.5" 1.3" 2.2" 🚿 Regular watering
Aug 3.5" 1.5" 2" 🚿 Regular watering
Sep 3.5" 1.1" 2.4" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Carbon 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 1,100 GDD Excellent fit

Broccoli Rabe Planting Timeline — Carbon County, WY

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 – May 10
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 17 May 17 – Jun 7
Harvest July 12 Jul 12 – Aug 16
Fall Sowing July 10 Jul 10 – Jul 24

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

110 days in Carbon County

Growing Tips for Broccoli Rabe in Carbon County

Direct sow Broccoli Rabe outdoors after May 31 in Carbon 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 Carbon County, WY?

Carbon County is in Zone 5a with an average last frost of May 31. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Carbon County, WY?

Carbon County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 31 and first fall frost is September 18.

🌱

Your Carbon County Garden Planner — Free

A 24-page printable planner built for Carbon 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Carbon County, WY. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.