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When to Plant Endive in Jefferson County, MT

Jefferson County, Montana Zone 5a May

Your May planting checklist for Jefferson County, Montana

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

Avg. last frost June 15
Avg. first frost September 7
Soil temp (4") 32°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
June prep starts now
  • Transplants going out: endive
  • Direct-sowing: endive
  • Fall sowing: endive

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Endive is a leafy green with a slightly bitter flavor, available in curly (frisee) and broad-leaved (escarole) types. It adds texture and complexity to salads.

Jefferson County, Montana is in USDA Zone 5a. The average last spring frost is June 15 and the first fall frost is September 7, giving you a growing season of approximately 84 days.

At an elevation of 7,214 feet, Jefferson County receives approximately 21.5 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Endive to ensure they mature before fall.

Jefferson County, MT (Zone 5a) Very short season
84 days
Last Spring Frost June 15
84 growing days
First Fall Frost September 7

Jefferson County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: May 5 Transplant: Jun 9 🍅 Harvest: Jul 28 – Sep 1
Recommended (50%) ✓ Fits season (0 days to spare)
Start indoors: May 11 Transplant: Jun 15 🍅 Harvest: Aug 3 – Sep 7
Safe Start (90%) ✓ Fits season (6 days to spare)
Start indoors: May 19 Transplant: Jun 23 🍅 Harvest: Aug 11 – Sep 15

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 Jefferson County

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

Soil pH

Your soil pH (6.4–7.9) is more alkaline than Endive prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Endive.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Endive.

How to Plant Endive

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Endive

2
successive plantings in your 84-day season

Sow every 5.1 weeks. Last sowing by Jul 04 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Endive

Endive needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Endive Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 2" 1" 💧 Light watering
Aug 3" 2" 1" 💧 Light watering
Sep 3" 2" 1" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Endive 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.

Endive needs ~632 GDD — county provides 966 GDD Excellent fit

Endive Planting Timeline — Jefferson County, MT

Endive Planting Calendar

Activity When Date Range
Start Indoors May 11 May 11 – May 25
Transplant Outdoors June 15 Jun 15 – Jun 29
Direct Sow June 1 Jun 1 – Jun 22
Harvest August 3 Aug 3 – Sep 7
Fall Sowing June 29 Jun 29 – Jul 13

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

84 days in Jefferson County

Growing Tips for Endive in Jefferson County

Direct sow Endive outdoors after June 15 in Jefferson County when soil has warmed and frost danger has passed.

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

General growing tips

Sow seeds directly in spring or fall. Blanch heads by tying outer leaves together 2-3 weeks before harvest to reduce bitterness. Keep soil evenly moist.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Endive in Jefferson County, MT?

Jefferson County is in Zone 5a with an average last frost of June 15. Plan your Endive planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, MT?

Jefferson County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 15 and first fall frost is September 7.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 5a). 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 Jefferson 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.