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When to plant Celery in Boundary County, ID

Boundary County's spring Celery window runs April 26 through May 17. time plantings around the expected last-frost window for best survival. A second sowing from July 14 to July 28 extends the harvest into fall.

When to Plant Celery in Boundary County, ID

Celery

Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.

Boundary County, Idaho is in USDA Zone 6a. The average last spring frost is May 10 and the first fall frost is September 22, giving you a growing season of approximately 135 days.

At an elevation of 5,105 feet, Boundary County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Celery during the growing season.

Boundary County, ID (Zone 6a) Short season
135 days
Last Spring Frost May 10
135 growing days
First Fall Frost September 22

Boundary County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Monthly Watering Guide for Celery

Celery needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Celery Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 1.8" 2.5" 🚿 Regular watering
Aug 4.3" 1.9" 2.4" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Celery Planting Timeline — Boundary County, ID

Celery Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 10 May 10 – May 24
Direct Sow April 26 Apr 26 – May 17
Harvest August 2 Aug 2 – Sep 27
Fall Sowing July 14 Jul 14 – Jul 28

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

High — keep soil consistently moist

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

135 days in Boundary County

Growing Tips for Boundary County

Start seeds indoors 10-12 weeks before last frost. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celery in Boundary County, ID?

Boundary County is in Zone 6a with an average last frost of May 10. Plan your Celery planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boundary County, ID?

Boundary County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 10 and first fall frost is September 22.

When should I plant Celery in Boundary County, ID?

In Boundary County, ID, plant Celery after the last frost (around May 10) and before the first frost (around September 22). Best results when soil holds above 50°F.

What growing zone is Boundary County, ID for Celery?

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

Can Celery grow in Boundary County's climate?

Yes — Celery grows well in Boundary County's temperate climate. Boundary County averages a 135-day frost-free season, with last frost around May 10 and first frost around September 22.

🌱

Your Boundary County Garden Planner — Free

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

Sources & credits

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