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When to Plant Broccoli Rabe in Fremont County, CO

Fremont County, Colorado Zone 6a May

Your May game plan for Fremont County, Colorado

We've pulled the most time-sensitive tasks for Fremont County, Colorado this May and put them front and centre. Tackle them in order.

Avg. last frost May 23
Avg. first frost September 25
Soil temp (4") 38°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
  1. Time to transplant broccoli rabe

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Sow broccoli rabe where they'll grow

    Your soil is 38°F — warm enough for these to germinate without babying.

Looking ahead to June
  • Starting indoors: 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.

Fremont County, Colorado is in USDA Zone 6a. The average last spring frost is May 23 and the first fall frost is September 25, giving you a growing season of approximately 125 days.

At an elevation of 6,575 feet, Fremont County receives approximately 18.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°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.

Fremont County, CO (Zone 6a) Short season
125 days
Last Spring Frost May 23
125 growing days
First Fall Frost September 25
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Fremont 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 (52 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jun 22 – Jul 27
Recommended (50%) ✓ Fits season (48 days to spare)
Start indoors: Apr 18 Transplant: May 23 🍅 Harvest: Jul 4 – Aug 8
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: May 11 Transplant: Jun 15 🍅 Harvest: Jul 27 – Aug 31

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 Fremont 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 Fremont County is excellent for Broccoli Rabe — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). 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 125-day season

Sow every 4.6 weeks. Last sowing by Jul 27 to harvest before frost.

For a dedicated fall crop, sow by Jul 17.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.6″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 238 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 1.5" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3.5" 2" 1.5" 💧 Light watering
Jun 3.5" 1.5" 2" 🚿 Regular watering
Jul 3.5" 1.4" 2.1" 🚿 Regular watering
Aug 3.5" 1.7" 1.8" 🚿 Regular watering
Sep 3.5" 1.5" 2" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Fremont 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 ~650 GDD — county provides 1,625 GDD Excellent fit

Broccoli Rabe Planting Timeline — Fremont County, CO

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 – May 2
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 9 May 9 – May 30
Harvest July 4 Jul 4 – Aug 8
Fall Sowing July 17 Jul 17 – Jul 31

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
July Fall Sowing Harvest
August Harvest
September
October
November
December
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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 6a

📆 Growing Season

125 days in Fremont County

Growing Tips for Broccoli Rabe in Fremont County

Direct sow Broccoli Rabe outdoors after May 23 in Fremont 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 Fremont County, CO?

Fremont County is in Zone 6a with an average last frost of May 23. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fremont County, CO?

Fremont County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 23 and first fall frost is September 25.

🌱

Your Fremont County Garden Planner — Free

A 24-page printable planner built for Fremont County (Zone 6a). 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 Fremont County, CO. 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.