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When to Plant Endive in Polk County, IA

Polk County, Iowa Zone 5a April

Your April gardening checklist

Your garden in Polk County, Iowa is working on a schedule, even when you're not. Here's where you should be this April.

Avg. last frost May 2
Avg. first frost October 7
Soil temp (4") 43°F
Watering High
Pest pressure Low
Daylight 13.1 hrs
  1. Outdoor sowing time: endive

    Your soil is 43°F — warm enough for these to germinate without babying.

Coming up in May — start thinking about
  • Transplants going out: endive

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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.

Polk County, Iowa is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 1,037 feet, Polk County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Endive during the growing season.

Polk County, IA (Zone 5a) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Polk County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (75 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jun 10 – Jul 15
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jun 20 – Jul 25
Safe Start (90%) ✓ Fits season (73 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jun 30 – Aug 4

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 Polk County

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

Soil pH

Your soil pH (6.0–6.8) is within Endive's preferred range (5.5–7.0).

Soil Texture

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

Drainage

Drainage is adequate for Endive.

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 158-day season

Sow every 5.1 weeks. Last sowing by Aug 03 to harvest before frost.

For a dedicated fall crop, sow by Jul 29.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 181 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.3" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 3" 3.9" 0" ✅ Rainfall sufficient
Jun 3" 4.1" 0" ✅ Rainfall sufficient
Jul 3" 3.3" 0" ✅ Rainfall sufficient
Aug 3" 3.1" 0" ✅ Rainfall sufficient
Sep 3" 3.1" 0" ✅ Rainfall sufficient
Oct 3" 2.1" 0.9" 💧 Light watering
Nov 1.9" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Polk 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 ~798 GDD — county provides 2,291 GDD Excellent fit

Endive Planting Timeline — Polk County, IA

Endive Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 18 Apr 18 – May 9
Harvest June 20 Jun 20 – Jul 25
Fall Sowing July 29 Jul 29 – Aug 12

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

158 days in Polk County

Growing Tips for Endive in Polk County

Direct sow Endive outdoors after May 02 in Polk 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 Polk County, IA?

Polk County is in Zone 5a with an average last frost of May 2. Plan your Endive planting based on this frost date — see the calendar above for exact timing.

What planting zone is Polk County, IA?

Polk County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 7.

🌱

Your Polk County Garden Planner — Free

A 24-page printable planner built for Polk 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 Polk 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.