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When to Plant Celtuce in Park County, CO

Park County, Colorado Zone 5b May

Your May planting checklist for Park County, Colorado

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Park County, Colorado.

Avg. last frost June 16
Avg. first frost September 4
Soil temp (4") 34°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
Get ahead of June
  • Transplants going out: celtuce
  • Direct-sowing: celtuce
  • Fall sowing: 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.

Park County, Colorado is in USDA Zone 5b. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.

At an elevation of 7,567 feet, Park County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Celtuce to ensure they mature before fall.

Park County, CO (Zone 5b) Very short season
80 days
Last Spring Frost June 16
80 growing days
First Fall Frost September 4
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Park County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Aug 12 – Sep 23
Recommended (50%) ✗ May not fit
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Aug 18 – Sep 29
Safe Start (90%) ✗ May not fit
Start indoors: May 22 Transplant: Jun 26 🍅 Harvest: Aug 28 – Oct 9

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 Park County

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

Soil pH

Your soil pH (6.2–7.6) overlaps with Celtuce's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Park 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 (2.6%). 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
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3.1" 0" ❄️ Dormant
Jun 3" 1.8" 1.2" 💧 Light watering
Jul 3" 2.2" 0.8" 💧 Light watering
Aug 3" 2.7" 0.3" 💧 Light watering
Sep 3" 1.8" 1.2" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Park 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 ~919 GDD — county provides 980 GDD Good fit

Celtuce Planting Timeline — Park County, CO

Celtuce Planting Calendar

Activity When Date Range
Start Indoors May 12 May 12 – May 26
Transplant Outdoors June 16 Jun 16 – Jun 30
Direct Sow June 2 Jun 2 – Jun 23
Harvest August 18 Aug 18 – Sep 29
Fall Sowing June 26 Jun 26 – Jul 10

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Start Indoors
June Transplant Outdoors Direct Sow Fall Sowing
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 · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

80 days in Park County

Growing Tips for Celtuce in Park County

Direct sow Celtuce outdoors after June 16 in Park County when soil has warmed and frost danger has passed.

Your 80.0-day growing season in Park 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 Park County, CO?

Park County is in Zone 5b with an average last frost of June 16. Plan your Celtuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Park County, CO?

Park County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 16 and first fall frost is September 4.

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Your Park County Garden Planner — Free

A 24-page printable planner built for Park 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 Park 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.