When to Plant Cayenne Pepper in Boulder, Colorado (80310)

Location

Boulder, Colorado

ZIP Code

80310

USDA Zone

Last Frost

Monday, April 20, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Monday, February 9, 2026

Transplant Outdoors

Monday, May 4, 2026

Based on last frost Monday, April 20, 2026 · Zone 6a

Pro tip: Start Cayenne Pepper seeds indoors 10 weeks before your last frost date, then transplant outdoors around Monday, May 4, 2026.

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🌿 Plant Details

Scientific Name Capsicum annuum

Days to Maturity 75 days

Mature Height 24-36"

Spread 18"

Type Bush

Fruit Size Small (2-5 inch pods)

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Moderate

↔️

Spacing

18" apart

🌱

Planting Depth

0.25" deep

Seeds typically germinate in 7-14 days

Ready to Plant Cayenne Pepper in Boulder?

Get your seeds now so they're ready by Monday, February 9, 2026.

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🤝 Good Companions

BasilCarrotTomato

⚠️ Avoid Planting Near

Fennel

🤝

Full Companion Planting Guide for Cayenne Pepper

See which plants help Cayenne Pepper 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 Cayenne Pepper Varieties

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

Ring of Fire

open-pollinated 60d

Hot, thin-walled cayenne that matures early and dries beautifully for flakes and powder.

Long Slim Cayenne

open-pollinated 70d

Classic 5–6 inch thin pepper with classic cayenne heat; great fresh or dried.

Golden Cayenne

open-pollinated 70d

Yellow version of the classic cayenne; slightly milder with a fruity undertone.

🌾 Seed Saving Guide

🟡 Moderate

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Let peppers ripen fully red before collecting seeds.

Processing

Cut open ripe peppers, carefully remove seeds, spread to dry 1–2 weeks. Wear gloves.

Seed Viability

Up to 2 years when stored cool, dark, and dry.

Pro Tip

Crosses with all Capsicum annuum peppers (bell, jalapeño, etc.). Isolate by 300 feet for pure seed.

🪴

Raised Bed Planting Guides

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

Frequently Asked Questions

When should I plant Cayenne Pepper in Boulder, Colorado? +

In Boulder (Zone 6a), start Cayenne Pepper seeds indoors around Monday, February 9, 2026 and transplant outdoors around Monday, May 4, 2026.

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

The average last spring frost date for Boulder, Colorado (ZIP 80310) is around Monday, April 20, 2026. This is based on NOAA climate normals for USDA Zone 6a.

How long does Cayenne Pepper take to grow? +

Cayenne Pepper typically matures in about 75 days from transplanting. In Boulder, that means you can expect harvest around Monday, May 4, 2026 plus 75 days.

Should I start Cayenne Pepper indoors or direct sow in Colorado? +

Cayenne Pepper should be started indoors 10 weeks before your last frost date. In Boulder, that means starting around Monday, February 9, 2026.

📚 More Cayenne Pepper Planting Guides

🗺️

Cayenne Pepper in Colorado

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 6a Cayenne Pepper Guide

All cities in your zone · Avg dates

→

Other Plants for Boulder

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Growing Cayenne Pepper in Zone 6a

Cayenne Pepper (Capsicum annuum) is a popular garden vegetable. In Boulder, Colorado, which is in USDA Hardiness Zone 6a, you should start seeds indoors around Monday, February 9, 2026.

Your average last frost date is Monday, April 20, 2026. Plan to transplant your Cayenne Pepper seedlings outdoors around Monday, May 4, 2026, about 2 weeks after your last frost date.