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When to plant Parsley in Cassia County County,

The best window to plant Parsley in Cassia County County, is May 1–May 22, when soil warms to 50°F. Last frost typically hits May 15; first frost October 1. A second sowing from July 23 to August 6 extends the harvest into fall.

When to Plant Parsley in Cassia County, ID

Parsley
Cassia County, Idaho Zone 6b June

This month in Cassia County, Idaho

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 15
Avg. first frost October 1
Soil temp (4") 43°F
Watering Critical
Pest pressure High
Daylight 15.1 hrs
  1. Sow parsley in trays indoors

    Label every cell. You will absolutely forget which is which otherwise.

A few tasks this June that'll pay off in July
  • First harvests: parsley
  • Fall sowing: parsley

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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.

Cassia County, Idaho is in USDA Zone 6b. The average last spring frost is May 15 and the first fall frost is October 1, giving you a growing season of approximately 139 days.

At an elevation of 8,089 feet, Cassia County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Parsley during the growing season. With low rainfall, drip irrigation is essential for growing Parsley successfully. Mulch heavily to conserve soil moisture.

Cassia County, ID (Zone 6b) Short season
139 days
Last Spring Frost May 15
139 growing days
First Fall Frost October 1

Cassia County Soil Profile

Soil Type

Loam

Soil pH

6.3-8.2

Drainage

Well Drained

Parsley Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Apr 4 Transplant: May 2 🍅 Harvest: Jul 4 – Sep 5
Recommended (50%) ✓ Fits season (20 days to spare)
Start indoors: Apr 10 Transplant: May 8 🍅 Harvest: Jul 10 – Sep 11
Safe Start (90%) ✓ Fits season (13 days to spare)
Start indoors: May 5 Transplant: Jun 2 🍅 Harvest: Aug 4 – Oct 6

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 Cassia County

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

Soil pH

Your soil pH (6.3–8.2) is more alkaline than Parsley prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Parsley.

How to Plant Parsley

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Parsley

2
successive plantings in your 139-day season

Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.

For a dedicated fall crop, sow by Jul 23.

Parsley Water Budget

Plant needs
0.6″/week
Rainfall provides
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 106 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 1.1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 1.8" 0" ❄️ Dormant
May 2.6" 2.3" 0.3" 💧 Light watering
Jun 2.6" 1.1" 1.5" 🚿 Regular watering
Jul 2.6" 1.5" 1.1" 💧 Light watering
Aug 2.6" 1.7" 0.9" 💧 Light watering
Sep 2.6" 1.3" 1.3" 🚿 Regular watering
Oct 2.6" 1.6" 1" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Cassia 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 ~1,068 GDD — county provides 2,119 GDD Excellent fit

Parsley Planting Timeline — Cassia County, ID

Parsley Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest July 10 Jul 10 – Sep 11
Fall Sowing July 23 Jul 23 – Aug 6

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
July Fall Sowing Harvest
August Fall Sowing Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.6"/week · Only during dry spells

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

139 days in Cassia County

Growing Tips for Parsley in Cassia County

Direct sow Parsley outdoors after May 15 in Cassia 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 Cassia County, ID?

Cassia County is in Zone 6b with an average last frost of May 15. Plan your Parsley planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cassia County, ID?

Cassia County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 15 and first fall frost is October 1.

When should I plant Parsley in Cassia County County, ?

In Cassia County County, , plant Parsley after the last frost (around May 15) and before the first frost (around October 1). Best results when soil holds above 50°F.

What growing zone is Cassia County County, for Parsley?

Cassia County County sits in USDA Zone 6b. Parsley grows reliably in zones 2a through 10b, so it's a good fit here.

Can Parsley grow in Cassia County County's climate?

Yes — Parsley grows well in Cassia County County's temperate climate. Cassia County County averages a 139-day frost-free season, with last frost around May 15 and first frost around October 1.

🌱

Your Cassia County Garden Planner — Free

A 22-page printable planner built for Cassia County (Zone 6b). 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 Cassia County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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