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When to plant Broccoli in Park County, CO

For Park County, gardeners: plant Broccoli June 2 through June 23 once soil reads 50°F. A second sowing from June 26 to July 10 extends the harvest into fall.

When to Plant Broccoli in Park County, CO

Broccoli

Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.

Park County, Colorado is in USDA Zone 5b. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.

At an elevation of 7,567 feet, Park County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Broccoli to ensure they mature before fall.

Park County, CO (Zone 5b) Very short season
80 days
Last Spring Frost June 16
80 growing days
First Fall Frost September 4

Park County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

How Much Broccoli to Grow

1-2 lbs
Average yield per plant
3
Plants per person
6 sq ft
Space per person

For a family of 4, plant approximately 12 broccoli plants in about 24 sq ft. In Park County's 80-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Monthly Watering Guide for Broccoli

Broccoli needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Broccoli Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3.1" 0" ❄️ Dormant
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2.7" 1.6" 💧 Light watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Park County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Broccoli Planting Timeline — Park County, CO

Broccoli Planting Calendar

Activity When Date Range
Start Indoors May 12 May 12 – May 26
Transplant Outdoors June 16 Jun 16 – Jun 30
Direct Sow June 2 Jun 2 – Jun 23
Harvest August 18 Aug 18 – Sep 29
Fall Sowing June 26 Jun 26 – Jul 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

80 days in Park County

Growing Tips for Park County

Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Broccoli Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow plants to flower 2nd year; collect dry pods.
Storage Store airtight; viable 5 years at 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in Park County, CO?

Park County is in Zone 5b with an average last frost of June 16. Plan your Broccoli planting based on this frost date — see the calendar above for exact timing.

What planting zone is Park County, CO?

Park County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 16 and first fall frost is September 4.

When should I plant Broccoli in Park County, CO?

In Park County, CO, plant Broccoli after the last frost (around June 16) and before the first frost (around September 4). Best results when soil holds above 50°F.

What growing zone is Park County, CO for Broccoli?

Park County sits in USDA Zone 5b. Broccoli grows reliably in zones 2a through 11b, so it's a good fit here.

Can Broccoli grow in Park County's climate?

Yes — Broccoli grows well in Park County's temperate climate. Park County averages a 80-day frost-free season, with last frost around June 16 and first frost around September 4.

🌱

Your Park County Garden Planner — Free

A 22-page printable planner built for Park County (Zone 5b). 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 Park County, CO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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