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When to Plant Parsley in Hardin County, IA

Parsley is a biennial herb available in flat-leaf (Italian) and curly varieties. It is a nutritional powerhouse rich in vitamins C and K and adds fresh flavor to countless dishes.

Hardin County, Iowa is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.

At an elevation of 507 feet, Hardin County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Parsley to ensure they mature before fall.

Hardin County, IA (Zone 4b) Moderate season
164 days
Last Spring Frost April 28
164 growing days
First Fall Frost October 9

Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (45 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jun 17 – Aug 19
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Jun 23 – Aug 25
Safe Start (90%) ✓ Fits season (41 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Jul 6 – Sep 7

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
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Parsley needs ~858 GDD — county provides 2,009 GDD Excellent fit

Parsley Planting Timeline โ€” Hardin County, IA

Parsley Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 โ€“ Mar 31
Transplant Outdoors April 21 Apr 21 โ€“ May 5
Direct Sow April 21 Apr 21 โ€“ May 12
Fall Sowing July 17 Jul 17 โ€“ Jul 31
Harvest June 23 Jun 23 โ€“ Aug 25

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“80 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4b

Growing Season

164 days

Growing Tips for Hardin County

Start seeds indoors 6-8 weeks before last frost. Soak seeds overnight as germination is slow. Harvest outer stems first to keep plants productive. Parsley attracts swallowtail butterflies.

Companion Planting

Good Companions

Avoid Planting Near

  • Mint
  • Lettuce

Level Up Your Garden

Frequently Asked Questions

When should I plant Parsley in Hardin County, IA?

Hardin County is in Zone 4b with an average last frost of April 28. Plan your Parsley planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Hardin County, IA?

Hardin County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Hardin County gardeners in Zone 4b 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 Hardin County, IA. Local conditions may vary. Last updated: April 2026.