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When to Plant Celtuce in Costilla County, CO

Costilla County, Colorado Zone 5b May

May in the garden — Costilla County, Colorado

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost June 8
Avg. first frost September 16
Soil temp (4") 43°F
Watering High
Pest pressure Low
Daylight 14 hrs
  1. Direct-sow celtuce

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Before June arrives, get these ready
  • Transplants going out: celtuce

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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.

Costilla County, Colorado is in USDA Zone 5b. The average last spring frost is June 8 and the first fall frost is September 16, giving you a growing season of approximately 100 days.

At an elevation of 5,598 feet, Costilla County receives approximately 21 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Celtuce during the growing season.

Costilla County, CO (Zone 5b) Short season
100 days
Last Spring Frost June 8
100 growing days
First Fall Frost September 16

Costilla County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Aug 1 – Sep 12
Recommended (50%) ✗ May not fit
Start indoors: May 4 Transplant: Jun 8 🍅 Harvest: Aug 10 – Sep 21
Safe Start (90%) ✗ May not fit
Start indoors: May 15 Transplant: Jun 19 🍅 Harvest: Aug 21 – Oct 2

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 Costilla County

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

Soil pH

Your soil pH (6.2–8.3) is more alkaline than Celtuce prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Celtuce.

Organic Matter

Organic matter is moderate (2.5%). 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.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.9″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 30 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 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 3" 1.3" 1.7" 🚿 Regular watering
Jul 3" 2" 1" 💧 Light watering
Aug 3" 2.5" 0.5" 💧 Light watering
Sep 3" 1.7" 1.3" 💧 Light watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Costilla 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 ~1,088 GDD — county provides 1,450 GDD Excellent fit

Celtuce Planting Timeline — Costilla County, CO

Celtuce Planting Calendar

Activity When Date Range
Start Indoors May 4 May 4 – May 18
Transplant Outdoors June 8 Jun 8 – Jun 22
Direct Sow May 25 May 25 – Jun 15
Harvest August 10 Aug 10 – Sep 21
Fall Sowing July 8 Jul 8 – Jul 22

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

Month-by-Month Timeline

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

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 5b

📆 Growing Season

100 days in Costilla County

Growing Tips for Celtuce in Costilla County

Direct sow Celtuce outdoors after June 08 in Costilla County when soil has warmed and frost danger has passed.

Your 100.0-day growing season in Costilla County is tight for Celtuce (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Costilla County, CO?

Costilla County is in Zone 5b with an average last frost of June 8. Plan your Celtuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Costilla County, CO?

Costilla County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 8 and first fall frost is September 16.

🌱

Your Costilla County Garden Planner — Free

A 24-page printable planner built for Costilla County (Zone 5b). 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 Costilla 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.