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When to Plant Celtuce in Jefferson County, IL

Jefferson County, Illinois Zone 6b May

Jefferson County, Illinois gardeners: here's your May plan

Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 9
Avg. first frost October 20
Soil temp (4") 65°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Get celtuce seeds going inside

    You're about 23 weeks out from your last frost — the perfect window to get these germinating indoors.

Get ahead of June
  • 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.

Jefferson County, Illinois is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 20, giving you a growing season of approximately 194 days.

At an elevation of 509 feet, Jefferson County receives approximately 34 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Celtuce during the growing season.

Jefferson County, IL (Zone 6b) Moderate season
194 days
Last Spring Frost April 9
194 growing days
First Fall Frost October 20

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Feb 28 Transplant: Apr 4 🍅 Harvest: Jun 6 – Jul 18
Recommended (50%) ✓ Fits season (89 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jun 11 – Jul 23
Safe Start (90%) ✓ Fits season (92 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 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 Jefferson County

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

Soil pH

Your soil pH (6.1–7.1) overlaps with Celtuce's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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 194-day season

Sow every 6.9 weeks. Last sowing by Jul 22 to harvest before frost.

For a dedicated fall crop, sow by Aug 11.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/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 1.4" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3" 3.2" 0" ✅ Rainfall sufficient
May 3" 4.3" 0" ✅ Rainfall sufficient
Jun 3" 3.9" 0" ✅ Rainfall sufficient
Jul 3" 3.8" 0" ✅ Rainfall sufficient
Aug 3" 3.4" 0" ✅ Rainfall sufficient
Sep 3" 3" 0" ✅ Rainfall sufficient
Oct 3" 2.9" 0.1" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jefferson 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 ~1,200 GDD — county provides 3,104 GDD Excellent fit

Celtuce Planting Timeline — Jefferson County, IL

Celtuce Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow March 26 Mar 26 – Apr 16
Harvest June 11 Jun 11 – Jul 23
Fall Sowing August 11 Aug 11 – Aug 25

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

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 6b

📆 Growing Season

194 days in Jefferson County

Growing Tips for Celtuce in Jefferson County

Direct sow Celtuce outdoors after April 09 in Jefferson 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 Jefferson County, IL?

Jefferson County is in Zone 6b with an average last frost of April 9. Plan your Celtuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, IL?

Jefferson County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 20.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson 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 Jefferson 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.