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When to Plant Parsley in Iron County, WI

Iron County, Wisconsin Zone 4a May

What to do in May

Here's what deserves your attention in Iron County, Wisconsin this month. Everything below is tailored to Zone 4a and timed around your local frost dates.

Avg. last frost May 22
Avg. first frost September 25
Soil temp (4") 50°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Harden off and plant parsley

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Outdoor sowing time: parsley

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

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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.

Iron County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is September 25, giving you a growing season of approximately 126 days.

At an elevation of 841 feet, Iron County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Parsley to ensure they mature before fall.

Iron County, WI (Zone 4a) Short season
126 days
Last Spring Frost May 22
126 growing days
First Fall Frost September 25

Iron County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (4 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jul 13 – Sep 14
Recommended (50%) ✓ Fits season (7 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Jul 17 – Sep 18
Safe Start (90%) ✓ Fits season (6 days to spare)
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Aug 1 – Oct 3

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.

Soil Compatibility in Iron County

How your county's soil matches Parsley's growing requirements.

Soil pH

Your soil pH (5.7–6.9) overlaps with Parsley's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Iron County is excellent for Parsley — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.6%) — Parsley will thrive.

How to Plant Parsley

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Parsley

2
successive plantings in your 126-day season

Sow every 6.9 weeks. Last sowing by Jul 07 to harvest before frost.

For a dedicated fall crop, sow by Jul 03.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Parsley

Parsley needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Parsley Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 2.6" 3.7" 0" ✅ Rainfall sufficient
Jun 2.6" 3.6" 0" ✅ Rainfall sufficient
Jul 2.6" 3.6" 0" ✅ Rainfall sufficient
Aug 2.6" 3.7" 0" ✅ Rainfall sufficient
Sep 2.6" 3.2" 0" ✅ Rainfall sufficient
Oct 2.5" 0" ❄️ Dormant
Nov 2.3" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Iron County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Parsley Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Parsley needs ~595 GDD — county provides 1,071 GDD Excellent fit

Parsley Planting Timeline — Iron County, WI

Parsley Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 15 May 15 – Jun 5
Harvest July 17 Jul 17 – Sep 18
Fall Sowing July 3 Jul 3 – Jul 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

126 days in Iron County

Growing Tips for Parsley in Iron County

Direct sow Parsley outdoors after May 22 in Iron County when soil has warmed and frost danger has passed.

Common pests for Parsley in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Parsley in Iron County, WI?

Iron County is in Zone 4a with an average last frost of May 22. Plan your Parsley planting based on this frost date — see the calendar above for exact timing.

What planting zone is Iron County, WI?

Iron County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is September 25.

🌱

Your Iron County Garden Planner — Free

A 24-page printable planner built for Iron County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Iron County, WI. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.