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When to Plant Lettuce in Warren County, IN

Warren County, Indiana Zone 6a May

Your May planting checklist for Warren County, Indiana

May is a pivotal month for Warren County, Indiana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 19
Avg. first frost October 14
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Fire up the seed-starting tray: lettuce

    These need a head start before your last frost (April 19). Sow into cells now so you're ready to transplant in a few weeks.

  2. Collect lettuce at their peak

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

A few tasks this May that'll pay off in June
  • First harvests: lettuce

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Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.

Warren County, Indiana is in USDA Zone 6a. The average last spring frost is April 19 and the first fall frost is October 14, giving you a growing season of approximately 178 days.

At an elevation of 764 feet, Warren County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Lettuce during the growing season.

Warren County, IN (Zone 6a) Moderate season
178 days
Last Spring Frost April 19
178 growing days
First Fall Frost October 14

Warren County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (73 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: May 19 – Jul 28
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: May 24 – Aug 2
Safe Start (90%) ✓ Fits season (72 days to spare)
Start indoors: Mar 31 Transplant: May 5 🍅 Harvest: Jun 9 – Aug 18

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 Warren County

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

Soil pH

Your soil pH (5.9–7.1) overlaps with Lettuce's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Lettuce

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 Lettuce

7
successive plantings in your 178-day season

Sow every 3.4 weeks. Last sowing by Aug 15 to harvest before frost.

For a dedicated fall crop, sow by Aug 05.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Lettuce

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

Month Lettuce Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3" 3.7" 0" ✅ Rainfall sufficient
May 3" 4.7" 0" ✅ Rainfall sufficient
Jun 3" 5.4" 0" ✅ Rainfall sufficient
Jul 3" 4.7" 0" ✅ Rainfall sufficient
Aug 3" 4.6" 0" ✅ Rainfall sufficient
Sep 3" 3.7" 0" ✅ Rainfall sufficient
Oct 3" 3.1" 0" ✅ Rainfall sufficient
Nov 2.7" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

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

Lettuce 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.

Lettuce needs ~652 GDD — county provides 2,581 GDD Excellent fit

Lettuce Planting Timeline — Warren County, IN

Lettuce Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors April 19 Apr 19 – May 3
Direct Sow April 5 Apr 5 – Apr 26
Harvest May 24 May 24 – Aug 2
Fall Sowing August 5 Aug 5 – Aug 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

30–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

178 days in Warren County

Growing Tips for Lettuce in Warren County

Direct sow Lettuce outdoors after April 19 in Warren County when soil has warmed and frost danger has passed.

Your generous 178.0-day season in Warren County allows multiple plantings of Lettuce. Sow every 15.0 days for continuous harvest.

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

General growing tips

Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.

Recommended Lettuce Varieties for Warren County

Bolt-resistant varieties for warm summers — grow as spring/fall crop

Jericho Muir Nevada New Red Fire

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Lettuce Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.
Storage Store airtight; viable 6 years at 35°F, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Frequently Asked Questions

When should I plant Lettuce in Warren County, IN?

Warren County is in Zone 6a with an average last frost of April 19. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Warren County, IN?

Warren County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 19 and first fall frost is October 14.

🌱

Your Warren County Garden Planner — Free

A 24-page printable planner built for Warren County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Warren County, IN. 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.