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When to Plant Parsley in Delaware 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.

Delaware County, Iowa is in USDA Zone 4b. 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 974 feet, Delaware County receives approximately 31.3 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.

Delaware County, IA (Zone 4b) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Delaware 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 (39 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: Jun 20 – Aug 22
Recommended (50%) ✓ Fits season (39 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jun 27 – Aug 29
Safe Start (90%) ✓ Fits season (34 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jul 11 – Sep 12

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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 236 gal / 100 sq ft
Parsley needs ~858 GDD — county provides 1,935 GDD Excellent fit

Parsley Planting Timeline โ€” Delaware County, IA

Parsley Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 โ€“ Apr 4
Transplant Outdoors April 25 Apr 25 โ€“ May 9
Direct Sow April 25 Apr 25 โ€“ May 16
Fall Sowing July 15 Jul 15 โ€“ Jul 29
Harvest June 27 Jun 27 โ€“ Aug 29

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 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

158 days

Growing Tips for Delaware 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 Delaware County, IA?

Delaware County is in Zone 4b with an average last frost of May 2. Plan your Parsley planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Delaware County, IA?

Delaware County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Delaware 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 Delaware County, IA. Local conditions may vary. Last updated: April 2026.