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When to Plant Parsley in Ravalli County, MT

Ravalli County, Montana Zone 5b May

May in the garden — Ravalli County, Montana

Each item below is timed to Ravalli County, Montana's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 21
Avg. first frost September 20
Soil temp (4") 34°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
  1. Transplant parsley outside

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Plant parsley from seed, right in the garden

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

June will be here before you know it — start on
  • Starting indoors: 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.

Ravalli County, Montana is in USDA Zone 5b. The average last spring frost is May 21 and the first fall frost is September 20, giving you a growing season of approximately 122 days.

At an elevation of 7,813 feet, Ravalli County receives approximately 15.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Parsley to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Parsley successfully. Mulch heavily to conserve soil moisture.

Ravalli County, MT (Zone 5b) Short season
122 days
Last Spring Frost May 21
122 growing days
First Fall Frost September 20
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Ravalli County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (4 days to spare)
Start indoors: Apr 7 Transplant: May 5 🍅 Harvest: Jul 7 – Sep 8
Recommended (50%) ✓ Fits season (3 days to spare)
Start indoors: Apr 16 Transplant: May 14 🍅 Harvest: Jul 16 – Sep 17
Safe Start (90%) ✓ Fits season (2 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 Ravalli County

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

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Parsley prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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 122-day season

Sow every 6.9 weeks. Last sowing by Jul 02 to harvest before frost.

For a dedicated fall crop, sow by Jul 12.

Plant 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 104 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 1.4" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 2.6" 1.8" 0.8" 💧 Light watering
Jun 2.6" 0.9" 1.7" 🚿 Regular watering
Jul 2.6" 1.5" 1.1" 💧 Light watering
Aug 2.6" 1.6" 1" 💧 Light watering
Sep 2.6" 1.1" 1.5" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Ravalli 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 ~910 GDD — county provides 1,586 GDD Excellent fit

Parsley Planting Timeline — Ravalli County, MT

Parsley Planting Calendar

Activity When Date Range
Start Indoors April 16 Apr 16 – Apr 30
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 16 Jul 16 – Sep 17
Fall Sowing July 12 Jul 12 – Jul 26

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 Harvest
September Harvest
October
November
December
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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 5b

📆 Growing Season

122 days in Ravalli County

Growing Tips for Parsley in Ravalli County

Direct sow Parsley outdoors after May 21 in Ravalli 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 Ravalli County, MT?

Ravalli County is in Zone 5b with an average last frost of May 21. Plan your Parsley planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ravalli County, MT?

Ravalli County, Montana is in USDA Hardiness Zone 5b. The average last spring frost is May 21 and first fall frost is September 20.

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Your Ravalli County Garden Planner — Free

A 24-page printable planner built for Ravalli County (Zone 5b). 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 Ravalli County, MT. 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.