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When to Plant Celtuce in Alamosa County, CO

Alamosa County, Colorado Zone 5a May

Alamosa County, Colorado gardeners: here's your May plan

Welcome to May in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 31
Avg. first frost September 19
Soil temp (4") 28°F
Watering High
Pest pressure Low
Daylight 14 hrs
  1. Harden off and plant celtuce

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Outdoor sowing time: celtuce

    Your soil is 28°F — warm enough for these to germinate without babying.

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Celtuce (stem lettuce) is a Chinese vegetable grown for its thick, crunchy stem rather than its leaves. The peeled stem has a mild, cucumber-like flavor.

Alamosa County, Colorado is in USDA Zone 5a. The average last spring frost is May 31 and the first fall frost is September 19, giving you a growing season of approximately 111 days.

At an elevation of 8,366 feet, Alamosa County receives approximately 18.3 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Celtuce to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Celtuce successfully. Mulch heavily to conserve soil moisture.

Alamosa County, CO (Zone 5a) Short season
111 days
Last Spring Frost May 31
111 growing days
First Fall Frost September 19
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Alamosa County Soil Profile

Soil Type

Loam

Soil pH

6.4-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Start indoors: Apr 21 Transplant: May 26 🍅 Harvest: Jul 28 – Sep 8
Recommended (50%) ✓ Fits season (6 days to spare)
Start indoors: Apr 26 Transplant: May 31 🍅 Harvest: Aug 2 – Sep 13
Safe Start (90%) ✓ Fits season (3 days to spare)
Start indoors: May 10 Transplant: Jun 14 🍅 Harvest: Aug 16 – Sep 27

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Alamosa County

How your county's soil matches Celtuce's growing requirements.

Soil pH

Your soil pH (6.4–8.0) is more alkaline than Celtuce prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Alamosa County is excellent for Celtuce — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Celtuce.

How to Plant Celtuce

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Celtuce

2
successive plantings in your 111-day season

Sow every 6.9 weeks. Last sowing by Jun 21 to harvest before frost.

For a dedicated fall crop, sow by Jul 11.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 9 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Celtuce

Celtuce needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Celtuce Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 3" 2" 1" 💧 Light watering
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 1.5" 1.5" 🚿 Regular watering
Aug 3" 1.9" 1.1" 💧 Light watering
Sep 3" 1.4" 1.6" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

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

Celtuce Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Celtuce needs ~806 GDD — county provides 1,193 GDD Excellent fit

Celtuce Planting Timeline — Alamosa County, CO

Celtuce Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 – May 10
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 17 May 17 – Jun 7
Harvest August 2 Aug 2 – Sep 13
Fall Sowing July 11 Jul 11 – Jul 25

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

111 days in Alamosa County

Growing Tips for Celtuce in Alamosa County

Direct sow Celtuce outdoors after May 31 in Alamosa County when soil has warmed and frost danger has passed.

Common pests for Celtuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or start indoors. Space 12 inches apart. Harvest when stems are about 1 inch in diameter. Peel the tough outer skin to reveal the tender center.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celtuce in Alamosa County, CO?

Alamosa County is in Zone 5a with an average last frost of May 31. Plan your Celtuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Alamosa County, CO?

Alamosa County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 31 and first fall frost is September 19.

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Your Alamosa County Garden Planner — Free

A 24-page printable planner built for Alamosa County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Alamosa County, CO. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.