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When to Plant Celtuce in Monroe County, IA

Monroe County, Iowa Zone 5b May

Your May planting checklist for Monroe County, Iowa

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 April 26
Avg. first frost October 13
Soil temp (4") 58°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
  1. Start celtuce indoors

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

A few tasks this May that'll pay off in 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.

Monroe County, Iowa is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 13, giving you a growing season of approximately 170 days.

At an elevation of 968 feet, Monroe County receives approximately 32.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Celtuce during the growing season.

Monroe County, IA (Zone 5b) Moderate season
170 days
Last Spring Frost April 26
170 growing days
First Fall Frost October 13
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Monroe County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: Jun 20 – Aug 1
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jun 28 – Aug 9
Safe Start (90%) ✓ Fits season (63 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 15 – Aug 26

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 Monroe County

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

Soil pH

Your soil pH (6.2–7.3) overlaps with Celtuce's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Monroe 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 170-day season

Sow every 6.9 weeks. Last sowing by Jul 15 to harvest before frost.

For a dedicated fall crop, sow by Aug 04.

Plant Water Budget

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

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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3" 2.8" 0.2" 💧 Light watering
May 3" 3.5" 0" ✅ Rainfall sufficient
Jun 3" 4.3" 0" ✅ Rainfall sufficient
Jul 3" 4" 0" ✅ Rainfall sufficient
Aug 3" 3.3" 0" ✅ Rainfall sufficient
Sep 3" 3" 0" ✅ Rainfall sufficient
Oct 3" 2.3" 0.7" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Monroe 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 ~1,144 GDD — county provides 2,592 GDD Excellent fit

Celtuce Planting Timeline — Monroe County, IA

Celtuce Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors April 26 Apr 26 – May 10
Direct Sow April 12 Apr 12 – May 3
Harvest June 28 Jun 28 – Aug 9
Fall Sowing August 4 Aug 4 – Aug 18

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5b

📆 Growing Season

170 days in Monroe County

Growing Tips for Celtuce in Monroe County

Direct sow Celtuce outdoors after April 26 in Monroe 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 Monroe County, IA?

Monroe County is in Zone 5b with an average last frost of April 26. Plan your Celtuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monroe County, IA?

Monroe County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 13.

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Your Monroe County Garden Planner — Free

A 24-page printable planner built for Monroe 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 Monroe County, IA. 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.