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When to Plant Kale in Warren County, IA

Kale is an exceptionally hardy, nutrient-dense green available in curly, lacinato, and Russian varieties. It tolerates heavy frost and often tastes sweeter after cold exposure.

Warren County, Iowa is in USDA Zone 5a. The average last spring frost is April 26 and the first fall frost is October 9, giving you a growing season of approximately 166 days.

At an elevation of 853 feet, Warren County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Kale during the growing season.

Warren County, IA (Zone 5a) Moderate season
166 days
Last Spring Frost April 26
166 growing days
First Fall Frost October 9

Warren County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: Jun 13 – Aug 8
Recommended (50%) ✓ Fits season (54 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jun 21 – Aug 16
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jul 6 – Aug 31

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.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.8″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 42 gal / 100 sq ft
Kale needs ~915 GDD — county provides 2,531 GDD Excellent fit

Kale Planting Timeline โ€” Warren County, IA

Kale Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 โ€“ Apr 5
Transplant Outdoors April 26 Apr 26 โ€“ May 10
Direct Sow April 12 Apr 12 โ€“ May 3
Fall Sowing July 31 Jul 31 โ€“ Aug 14
Harvest June 21 Jun 21 โ€“ Aug 16

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“70 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

166 days

Growing Tips for Warren County

Direct sow or transplant in early spring or late summer. Harvest outer leaves first to keep plants productive. Kale overwinters in many climates and can provide greens all year.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Level Up Your Garden

๐ŸŒพ Save Your Own Kale Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow 2nd year flower stalks to dry. Harvest pods when tan.
Storage Store airtight; viable 5 years at 35ยฐF, under 50% humidity.

Isolate 1/2 mile from other brassicas (broccoli, cabbage, etc.) โ€” they all cross.

Frequently Asked Questions

When should I plant Kale in Warren County, IA?

Warren County is in Zone 5a with an average last frost of April 26. Plan your Kale planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Warren County, IA?

Warren County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 26 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Warren County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Warren County, IA. Local conditions may vary. Last updated: April 2026.