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When to Plant Celtuce in Clark County, IL

Clark County, Illinois Zone 6b May

Top priorities for Clark County, Illinois gardeners in May

Here's what deserves your attention in Clark County, Illinois this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost April 14
Avg. first frost October 17
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Time to start celtuce inside

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

June prep starts now
  • First harvests: 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.

Clark County, Illinois is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 591 feet, Clark County receives approximately 41.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Celtuce during the growing season.

Clark County, IL (Zone 6b) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17
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Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (81 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jun 11 – Jul 23
Recommended (50%) ✓ Fits season (81 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 28
Safe Start (90%) ✓ Fits season (81 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 30 – Aug 11

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 Clark County

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

Soil pH

Your soil pH (6.2–6.8) is within Celtuce's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.9%) — Celtuce will thrive.

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

3
successive plantings in your 186-day season

Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.

For a dedicated fall crop, sow by Aug 08.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.9″/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 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3" 4.3" 0" ✅ Rainfall sufficient
May 3" 4.5" 0" ✅ Rainfall sufficient
Jun 3" 5.4" 0" ✅ Rainfall sufficient
Jul 3" 4.1" 0" ✅ Rainfall sufficient
Aug 3" 4.7" 0" ✅ Rainfall sufficient
Sep 3" 4" 0" ✅ Rainfall sufficient
Oct 3" 3.6" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clark 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 ~1,312 GDD — county provides 3,255 GDD Excellent fit

Celtuce Planting Timeline — Clark County, IL

Celtuce Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest June 16 Jun 16 – Jul 28
Fall Sowing August 8 Aug 8 – Aug 22

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May
June Harvest
July Harvest
August Fall Sowing
September
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: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

186 days in Clark County

Growing Tips for Celtuce in Clark County

Direct sow Celtuce outdoors after April 14 in Clark 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 Clark County, IL?

Clark County is in Zone 6b with an average last frost of April 14. Plan your Celtuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, IL?

Clark County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 17.

🌱

Your Clark County Garden Planner — Free

A 24-page printable planner built for Clark County (Zone 6b). 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 Clark County, IL. 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.