When should I plant Lettuce in Colorado?

Planting dates for Lettuce in Colorado vary by zone. Colorado spans zones 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a.

When to Plant Lettuce in Adams County, CO

Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.

Adams County, Colorado is in USDA Zone 5b. The average last spring frost is May 4 and the first fall frost is October 5, giving you a growing season of approximately 154 days.

At an elevation of 5,827 feet, Adams County receives approximately 23.9 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Lettuce during the growing season.

Adams County, CO (Zone 5b) Moderate season

154 days

❄

Last Spring Frost May 4

➔ 154 growing days ➔

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First Fall Frost October 5

Adams County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Zone Compatibility for Lettuce Zones 2a – 11b

1a 1b 2a 2b 3a 3b 4a 4b 5a 5b You 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a 11b 12a 12b 13a 13b

Ideal (data available) Suitable Marginal Not recommended

Lettuce Planting Timeline — Adams County, CO

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Last Frost

First Frost

Start Indoors

Mar 30 – Apr 13

Transplant

May 4 – May 18

Direct Sow

Apr 20 – May 11

Fall Sowing

Jul 27 – Aug 10

Harvest

Jun 8 – Aug 17

Growing season Start indoors Transplant Direct sow Harvest

Lettuce Planting Calendar

Activity	When	Date Range
Start Indoors	March 30	Mar 30 – Apr 13
Transplant Outdoors	May 4	May 4 – May 18
Direct Sow	April 20	Apr 20 – May 11
Harvest	June 8	Jun 8 – Aug 17
Fall Sowing	July 27	Jul 27 – Aug 10

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

30–60 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

154 days in Adams County

Growing Tips for Adams County

Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.

Companion Planting

Good Companions

Avoid Planting Near

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Lettuce Seeds

Life Cycle Annual

Pollination Self-Pollinating

How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.

Storage Store airtight; viable 6 years at 35°F, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Get our full Seed Saving Guide for 200 plants →

Lettuce in Other Locations

Frequently Asked Questions

When should I plant Lettuce in Adams County, CO?

Adams County is in Zone 5b with an average last frost of May 4. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adams County, CO?

Adams County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 4 and first fall frost is October 5.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — designed to help Adams County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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