When to Plant Lemongrass 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 18, 2026

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

Pro tip: Start Lemongrass seeds indoors 10 weeks before your last frost date, then transplant outdoors around Monday, May 18, 2026.

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🌿 Plant Details

Scientific Name Cymbopogon citratus

Days to Maturity 100 days

Mature Height 36-60"

Spread 36"

Type Tropical Perennial

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Moderate-High (1-2 inches/week)

↔️

Spacing

24" apart

🌱

Planting Depth

0.5" deep

Seeds typically germinate in 10-21 days

Ready to Plant Lemongrass in Boulder?

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

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🤝 Good Companions

TomatoBasilPepper

🤝

Full Companion Planting Guide for Lemongrass

See which plants help Lemongrass 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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🌾 Seed Saving Guide

🪴 Vegetative propagation

Propagate vegetatively, not by seed

Lemongrass rarely flowers in temperate climates. Propagate by dividing clumps in spring.

Division is the standard propagation method — separate outer stalks with roots attached and replant.

🪴

Raised Bed Planting Guides

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

Frequently Asked Questions

When should I plant Lemongrass in Boulder, Colorado? +

In Boulder (Zone 6a), start Lemongrass seeds indoors around Monday, February 9, 2026 and transplant outdoors around Monday, May 18, 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 Lemongrass take to grow? +

Lemongrass typically matures in about 100 days from transplanting. In Boulder, that means you can expect harvest around Monday, May 18, 2026 plus 100 days.

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

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

📚 More Lemongrass Planting Guides

🗺️

Lemongrass in Colorado

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 6a Lemongrass Guide

All cities in your zone · Avg dates

→

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Growing Lemongrass in Zone 6a

Lemongrass (Cymbopogon citratus) 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 Lemongrass seedlings outdoors around Monday, May 18, 2026, about 4 weeks after your last frost date.