When to Plant Cauliflower in Amherst, Colorado (80721)

Location

Amherst, Colorado

ZIP Code

80721

USDA Zone

Last Frost

Saturday, April 25, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Saturday, March 14, 2026

Transplant Outdoors

Saturday, April 25, 2026

Based on last frost Saturday, April 25, 2026 · Zone 5b

Pro tip: Start Cauliflower seeds indoors 6 weeks before your last frost date, then transplant outdoors around Saturday, April 25, 2026.

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🌿 Plant Details

Scientific Name Brassica oleracea var. botrytis

Days to Maturity 75 days

Mature Height 18-24"

Spread 24"

Type Head

Fruit Size Medium (6-8 inch head)

☀️ Growing Requirements

☀️

Sun

Full Sun (6 hours)

💧

Water

Regular (1-1.5 inches/week)

↔️

Spacing

18" apart

🌱

Planting Depth

0.5" deep

Seeds typically germinate in 4-10 days

Ready to Plant Cauliflower in Amherst?

Get your seeds now so they're ready by Saturday, March 14, 2026.

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🤝 Good Companions

BeetCeleryBeanOnion

⚠️ Avoid Planting Near

StrawberryTomato

🤝

Full Companion Planting Guide for Cauliflower

See which plants help Cauliflower thrive, which to keep away, and raised bed layout tips →

🛠️ Supplies You'll Need

🌱 Seed Starting Trays 🪴 Seed Starting Mix 💡 Grow Lights 🌡️ Heat Mat 🪵 Raised Garden Bed 🌍 Vegetable Garden Soil 🛠️ Hand Trowel Set 🚿 Watering Can

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Common Cauliflower Varieties

Popular cultivars to look for at your local nursery or seed supplier.

Snowball Y Improved

white 68d

Classic white cauliflower with dense, tight curds; reliable and widely adapted.

Cheddar

colored 68d

Orange-headed variety with a mild, buttery flavor and high beta-carotene content.

Graffiti

colored 80d

Brilliant purple cauliflower that holds its color when roasted; slightly nutty flavor.

Romanesco

specialty 80d

Lime-green logarithmic spirals with a mild, nutty taste; equally vegetable and art piece.

🌾 Seed Saving Guide

🔴 Difficult

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Allow head to bloom fully after the eating stage. Harvest seed pods when dry and tan.

Processing

Thresh dried seed stalks, winnow seeds from chaff.

Seed Viability

Up to 5 years when stored cool, dark, and dry.

Pro Tip

B. oleracea — crosses with all other oleracea cole crops. Very difficult to keep pure at home scale.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 14 plants of Cauliflower. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Cauliflower in Amherst, Colorado? +

In Amherst (Zone 5b), start Cauliflower seeds indoors around Saturday, March 14, 2026 and transplant outdoors around Saturday, April 25, 2026.

What is the last frost date for Amherst, Colorado? +

The average last spring frost date for Amherst, Colorado (ZIP 80721) is around Saturday, April 25, 2026. This is based on NOAA climate normals for USDA Zone 5b.

How long does Cauliflower take to grow? +

Cauliflower typically matures in about 75 days from transplanting. In Amherst, that means you can expect harvest around Saturday, April 25, 2026 plus 75 days.

Should I start Cauliflower indoors or direct sow in Colorado? +

Cauliflower should be started indoors 6 weeks before your last frost date. In Amherst, that means starting around Saturday, March 14, 2026.

📚 More Cauliflower Planting Guides

🗺️

Cauliflower in Colorado

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 5b Cauliflower Guide

All cities in your zone · Avg dates

→

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Growing Cauliflower in Zone 5b

Cauliflower (Brassica oleracea var. botrytis) is a popular garden vegetable. In Amherst, Colorado, which is in USDA Hardiness Zone 5b, you should start seeds indoors around Saturday, March 14, 2026.

Your average last frost date is Saturday, April 25, 2026. Plan to transplant your Cauliflower seedlings outdoors around Saturday, April 25, 2026, about 0 weeks after your last frost date.