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When to Plant Endive in Plymouth County, IA

Plymouth County, Iowa Zone 5a April

April in Plymouth County, Iowa — your action list

Here's what deserves your attention in Plymouth County, Iowa this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost April 30
Avg. first frost October 6
Soil temp (4") 41°F
Watering Low
Pest pressure Low
Daylight 13.2 hrs
  1. Transplant endive outside

    Your last frost (April 30) has passed. These warm-season crops can handle outdoor soil now.

  2. Plant endive from seed, right in the garden

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

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Endive is a leafy green with a slightly bitter flavor, available in curly (frisee) and broad-leaved (escarole) types. It adds texture and complexity to salads.

Plymouth County, Iowa is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 6, giving you a growing season of approximately 159 days.

At an elevation of 1,392 feet, Plymouth County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Endive to ensure they mature before fall.

Plymouth County, IA (Zone 5a) Moderate season
159 days
Last Spring Frost April 30
159 growing days
First Fall Frost October 6
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Plymouth County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Jun 9 – Jul 14
Recommended (50%) ✓ Fits season (75 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 18 – Jul 23
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Jul 2 – Aug 6

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 Plymouth County

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

Soil pH

Your soil pH (6.0–7.2) overlaps with Endive's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Endive will thrive.

How to Plant Endive

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 Endive

4
successive plantings in your 159-day season

Sow every 5.1 weeks. Last sowing by Aug 02 to harvest before frost.

For a dedicated fall crop, sow by Jul 28.

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 Endive

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

Month Endive Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3" 3.9" 0" ✅ Rainfall sufficient
May 3" 4.8" 0" ✅ Rainfall sufficient
Jun 3" 4.2" 0" ✅ Rainfall sufficient
Jul 3" 4.4" 0" ✅ Rainfall sufficient
Aug 3" 4.3" 0" ✅ Rainfall sufficient
Sep 3" 3.4" 0" ✅ Rainfall sufficient
Oct 3" 2.7" 0.3" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Endive 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.

Endive needs ~674 GDD — county provides 1,947 GDD Excellent fit

Endive Planting Timeline — Plymouth County, IA

Endive Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 16 Apr 16 – May 7
Harvest June 18 Jun 18 – Jul 23
Fall Sowing July 28 Jul 28 – Aug 11

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 Fall Sowing Harvest
August Fall Sowing
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

159 days in Plymouth County

Growing Tips for Endive in Plymouth County

Direct sow Endive outdoors after April 30 in Plymouth County when soil has warmed and frost danger has passed.

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

General growing tips

Sow seeds directly in spring or fall. Blanch heads by tying outer leaves together 2-3 weeks before harvest to reduce bitterness. Keep soil evenly moist.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Endive in Plymouth County, IA?

Plymouth County is in Zone 5a with an average last frost of April 30. Plan your Endive planting based on this frost date — see the calendar above for exact timing.

What planting zone is Plymouth County, IA?

Plymouth County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 6.

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Your Plymouth County Garden Planner — Free

A 24-page printable planner built for Plymouth County (Zone 5a). 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 Plymouth County, IA. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.