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When to plant Celery in Roosevelt County, MT

Plant Celery in Roosevelt County from May 10 to May 31 in spring. Roosevelt County sits in USDA Zone 4a, with last frost around May 17 and first frost on September 18. A second sowing from June 26 to July 10 extends the harvest into fall.

When to Plant Celery in Roosevelt County, MT

Celery
Roosevelt County, Montana Zone 4a August

August in the garden — Roosevelt County, Montana

Your Roosevelt County, Montana garden is entering a new phase. Here's what's on the schedule for August and why each task matters now.

Avg. last frost May 17
Avg. first frost September 18
Soil temp (4") 46°F
Watering High
Pest pressure Moderate
Daylight 14.1 hrs
  1. Harvest celery as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Before September arrives, get these ready
  • First harvests: celery

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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.

Roosevelt County, Montana is in USDA Zone 4a. The average last spring frost is May 17 and the first fall frost is September 18, giving you a growing season of approximately 124 days.

At an elevation of 7,123 feet, Roosevelt County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 78°F, so choose short-season varieties of Celery to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Celery successfully. Mulch heavily to conserve soil moisture.

Roosevelt County, MT (Zone 4a) Short season
124 days
Last Spring Frost May 17
124 growing days
First Fall Frost September 18

Roosevelt County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Celery Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 1 Transplant: May 13 🍅 Harvest: Aug 5 – Sep 30
Recommended (50%) ✗ May not fit
Start indoors: Apr 5 Transplant: May 17 🍅 Harvest: Aug 9 – Oct 4
Safe Start (90%) ✗ May not fit
Start indoors: Apr 22 Transplant: Jun 3 🍅 Harvest: Aug 26 – Oct 21

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 Roosevelt County

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

Soil pH

Your soil pH (6.7–7.7) is more alkaline than Celery prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Celery.

How to Plant Celery

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Celery Water Budget

Plant needs
1.3″/week
Rainfall provides
0.7″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 833 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Celery

Celery needs approximately 1.3 inches of water per week (5.6" 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 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 5.6" 2.3" 3.3" 🚿 Regular watering
Jun 5.6" 1.5" 4.1" 🚿 Regular watering
Jul 5.6" 1.6" 4" 🚿 Regular watering
Aug 5.6" 1.9" 3.7" 🚿 Regular watering
Sep 5.6" 1.7" 3.9" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

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

Celery 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.

Celery needs ~850 GDD — county provides 1,054 GDD Good fit

Celery Planting Timeline — Roosevelt County, MT

Celery Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 17 May 17 – May 31
Direct Sow May 10 May 10 – May 31
Harvest August 9 Aug 9 – Oct 4
Fall Sowing June 26 Jun 26 – Jul 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · 2-3 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

124 days in Roosevelt County

Growing Tips for Celery in Roosevelt County

Direct sow Celery outdoors after May 17 in Roosevelt County when soil has warmed and frost danger has passed.

Your 124.0-day growing season in Roosevelt County is tight for Celery (80.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Roosevelt County receives only 20" of rain annually. Celery needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

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 Roosevelt County, MT?

Roosevelt County is in Zone 4a with an average last frost of May 17. Plan your Celery planting based on this frost date — see the calendar above for exact timing.

What planting zone is Roosevelt County, MT?

Roosevelt County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 17 and first fall frost is September 18.

When should I plant Celery in Roosevelt County, MT?

In Roosevelt County, MT, plant Celery after the last frost (around May 17) and before the first frost (around September 18). Best results when soil holds above 50°F.

What growing zone is Roosevelt County, MT for Celery?

Roosevelt County sits in USDA Zone 4a. Celery grows reliably in zones 2a through 10b, so it's a good fit here.

Can Celery grow in Roosevelt County's climate?

Yes — Celery grows well in Roosevelt County's temperate climate. Roosevelt County averages a 124-day frost-free season, with last frost around May 17 and first frost around September 18.

🌱

Your Roosevelt County Garden Planner — Free

A 22-page printable planner built for Roosevelt 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 Roosevelt County, MT. Local conditions may vary. Last updated: August 2026.

Sources & credits

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