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When to Plant Parsley in Bonner County, ID

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.

Bonner County, Idaho is in USDA Zone 5b. The average last spring frost is May 5 and the first fall frost is October 3, giving you a growing season of approximately 151 days.

At an elevation of 7,480 feet, Bonner County receives approximately 12.9 inches of rainfall annually with predominantly loam soil. Summer highs average 86ยฐF, 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.

Bonner County, ID (Zone 5b) Moderate season
151 days
Last Spring Frost May 5
151 growing days
First Fall Frost October 3

Bonner County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Mar 24 Transplant: Apr 21 🍅 Harvest: Jun 23 – Aug 25
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Mar 31 Transplant: Apr 28 🍅 Harvest: Jun 30 – Sep 1
Safe Start (90%) ✓ Fits season (27 days to spare)
Start indoors: Apr 27 Transplant: May 25 🍅 Harvest: Jul 27 – Sep 28

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 Bonner County

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

Soil pH

Your soil pH (6.4โ€“8.2) is more alkaline than Parsley prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Bonner County is excellent for Parsley โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). 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 151-day season

Sow every 6.9 weeks. Last sowing by Jul 15 to harvest before frost.

For a dedicated fall crop, sow by Jul 25.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.4″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 389 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” 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 โ€” 0.9" 0" โ„๏ธ Dormant
Feb โ€” 0.7" 0" โ„๏ธ Dormant
Mar โ€” 1.1" 0" โ„๏ธ Dormant
Apr โ€” 1.5" 0" โ„๏ธ Dormant
May 2.6" 1.5" 1.1" ๐Ÿ’ง Light watering
Jun 2.6" 0.9" 1.7" ๐Ÿšฟ Regular watering
Jul 2.6" 1.1" 1.5" ๐Ÿšฟ Regular watering
Aug 2.6" 1.2" 1.4" ๐Ÿšฟ Regular watering
Sep 2.6" 1.1" 1.5" ๐Ÿšฟ Regular watering
Oct 2.6" 1.1" 1.5" ๐Ÿšฟ Regular watering
Nov โ€” 0.9" 0" โ„๏ธ Dormant
Dec โ€” 0.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Bonner County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,015 GDD — county provides 2,189 GDD Excellent fit

Parsley Planting Timeline โ€” Bonner County, ID

Parsley Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 โ€“ Apr 14
Transplant Outdoors April 28 Apr 28 โ€“ May 12
Direct Sow April 21 Apr 21 โ€“ May 12
Harvest June 30 Jun 30 โ€“ Sep 1
Fall Sowing July 25 Jul 25 โ€“ Aug 8

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 Fall Sowing Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

0.6"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

60โ€“80 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

151 days in Bonner County

Growing Tips for Parsley in Bonner County

Direct sow Parsley outdoors after May 05 in Bonner 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 Bonner County, ID?

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

What planting zone is Bonner County, ID?

Bonner County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 5 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Bonner County gardeners in Zone 5b 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 Bonner County, ID. Local conditions may vary. Last updated: April 2026.