Blog

When to Plant Parsley in Union 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.

Union County, Iowa is in USDA Zone 5a. The average last spring frost is April 23 and the first fall frost is October 11, giving you a growing season of approximately 171 days.

At an elevation of 1,311 feet, Union County receives approximately 39 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.

Union County, IA (Zone 5a) Moderate season
171 days
Last Spring Frost April 23
171 growing days
First Fall Frost October 11

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Mar 13 Transplant: Apr 10 🍅 Harvest: Jun 12 – Aug 14
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Mar 19 Transplant: Apr 16 🍅 Harvest: Jun 18 – Aug 20
Safe Start (90%) ✓ Fits season (49 days to spare)
Start indoors: Apr 4 Transplant: May 2 🍅 Harvest: Jul 4 – Sep 5

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
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 64 gal / 100 sq ft
Parsley needs ~858 GDD — county provides 2,094 GDD Excellent fit

Parsley Planting Timeline โ€” Union County, IA

Parsley Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 โ€“ Apr 2
Transplant Outdoors April 16 Apr 16 โ€“ Apr 30
Direct Sow April 9 Apr 9 โ€“ Apr 30
Fall Sowing August 2 Aug 2 โ€“ Aug 16
Harvest June 18 Jun 18 โ€“ Aug 20

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May โ€”
June Harvest
July Harvest
August Fall Sowing 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 5a

Growing Season

171 days

Growing Tips for Union 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 Union County, IA?

Union County is in Zone 5a with an average last frost of April 23. Plan your Parsley planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, IA?

Union County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 23 and first fall frost is October 11.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Union County, IA. Local conditions may vary. Last updated: April 2026.