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When to Plant Parsley in Washington County, MO

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.

Washington County, Missouri is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 24, giving you a growing season of approximately 197 days.

At an elevation of 738 feet, Washington County receives approximately 36.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Parsley during the growing season.

Washington County, MO (Zone 6b) Moderate season
197 days
Last Spring Frost April 10
197 growing days
First Fall Frost October 24

Washington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (75 days to spare)
Start indoors: Mar 1 Transplant: Mar 29 🍅 Harvest: May 31 – Aug 2
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Mar 6 Transplant: Apr 3 🍅 Harvest: Jun 5 – Aug 7
Safe Start (90%) ✓ Fits season (76 days to spare)
Start indoors: Mar 20 Transplant: Apr 17 🍅 Harvest: Jun 19 – Aug 21

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
0.3″/week
Watering frequency Only during dry spells
Season total 462 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Parsley needs ~1,015 GDD — county provides 2,856 GDD Excellent fit

Parsley Planting Timeline โ€” Washington County, MO

Parsley Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 โ€“ Mar 20
Transplant Outdoors April 3 Apr 3 โ€“ Apr 17
Direct Sow March 27 Mar 27 โ€“ Apr 17
Fall Sowing August 15 Aug 15 โ€“ Aug 29
Harvest June 5 Jun 5 โ€“ Aug 7

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors Direct Sow
April 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 6b

Growing Season

197 days

Growing Tips for Washington 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 Washington County, MO?

Washington County is in Zone 6b with an average last frost of April 10. Plan your Parsley planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Washington County, MO?

Washington County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Washington County gardeners in Zone 6b 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 Washington County, MO. Local conditions may vary. Last updated: April 2026.