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When to Plant Escarole in Petroleum County, MT

Petroleum County, Montana Zone 4b May

May to-do list for Petroleum County, Montana

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Petroleum County, Montana.

Avg. last frost May 18
Avg. first frost September 24
Soil temp (4") 30°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Set out escarole seedlings

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

  2. Scatter escarole into prepared beds

    Your soil is 30°F — warm enough for these to germinate without babying.

Before June arrives, get these ready
  • Starting indoors: escarole

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Escarole is a broad-leaved endive with slightly bitter, sturdy leaves. The outer leaves are more bitter while the blanched heart is tender and mild.

Petroleum County, Montana is in USDA Zone 4b. The average last spring frost is May 18 and the first fall frost is September 24, giving you a growing season of approximately 129 days.

At an elevation of 8,358 feet, Petroleum County receives approximately 13.7 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Escarole to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Escarole successfully. Mulch heavily to conserve soil moisture.

Petroleum County, MT (Zone 4b) Short season
129 days
Last Spring Frost May 18
129 growing days
First Fall Frost September 24

Petroleum County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jul 6 – Aug 3
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Jul 13 – Aug 10
Safe Start (90%) ✓ Fits season (48 days to spare)
Start indoors: Apr 18 Transplant: May 30 🍅 Harvest: Jul 25 – Aug 22

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 Petroleum County

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

Soil pH

Your soil pH (6.8–8.2) is more alkaline than Escarole prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Escarole.

Organic Matter

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

How to Plant Escarole

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Escarole

2
successive plantings in your 129-day season

Sow every 5.7 weeks. Last sowing by Jul 16 to harvest before frost.

For a dedicated fall crop, sow by Jul 02.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,177 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Escarole

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

Month Escarole Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 4.3" 1.8" 2.5" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 1.2" 3.1" 🚿 Regular watering
Aug 4.3" 1.5" 2.8" 🚿 Regular watering
Sep 4.3" 1.2" 3.1" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Escarole 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.

Escarole needs ~645 GDD — county provides 1,386 GDD Excellent fit

Escarole Planting Timeline — Petroleum County, MT

Escarole Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 11 May 11 – Jun 1
Harvest July 13 Jul 13 – Aug 10
Fall Sowing July 2 Jul 2 – Jul 16

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

129 days in Petroleum County

Growing Tips for Escarole in Petroleum County

Direct sow Escarole outdoors after May 18 in Petroleum County when soil has warmed and frost danger has passed.

Common pests for Escarole in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Petroleum County receives only 14" of rain annually. Escarole needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow in spring or late summer. Blanch heads by tying outer leaves together or covering with a pot for 2 weeks before harvest. Excellent braised or in soups.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Escarole in Petroleum County, MT?

Petroleum County is in Zone 4b with an average last frost of May 18. Plan your Escarole planting based on this frost date — see the calendar above for exact timing.

What planting zone is Petroleum County, MT?

Petroleum County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 18 and first fall frost is September 24.

🌱

Your Petroleum County Garden Planner — Free

A 24-page printable planner built for Petroleum County (Zone 4b). 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 Petroleum 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.