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When to Plant Belgian Endive in San Juan County, CO

San Juan County, Colorado Zone 5a May

May in San Juan County, Colorado — your action list

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

Avg. last frost June 18
Avg. first frost September 8
Soil temp (4") 32°F
Watering High
Pest pressure Low
Daylight 14 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: belgian endive
  • Direct-sowing: belgian endive
  • Fall sowing: belgian endive

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Belgian endive is produced by forcing chicory roots in darkness to create tight, pale, torpedo-shaped heads called chicons. They have a mild bitterness and elegant crunch.

San Juan County, Colorado is in USDA Zone 5a. The average last spring frost is June 18 and the first fall frost is September 8, giving you a growing season of approximately 82 days.

At an elevation of 7,539 feet, San Juan County receives approximately 20.1 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Belgian Endive to ensure they mature before fall.

San Juan County, CO (Zone 5a) Very short season
82 days
Last Spring Frost June 18
82 growing days
First Fall Frost September 8
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San Juan County Soil Profile

Soil Type

Loam

Soil pH

6.3-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 3 Transplant: Jun 7 🍅 Harvest: Sep 27 – Nov 22
Recommended (50%) ✗ May not fit
Start indoors: May 14 Transplant: Jun 18 🍅 Harvest: Oct 8 – Dec 3
Safe Start (90%) ✗ May not fit
Start indoors: May 25 Transplant: Jun 29 🍅 Harvest: Oct 19 – Dec 14

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 San Juan County

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

Soil pH

Your soil pH (6.3–8.0) is more alkaline than Belgian Endive prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Belgian Endive.

Organic Matter

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

How to Plant Belgian 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 237 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Belgian Endive

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

Month Belgian Endive Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.4" 0" ❄️ Dormant
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Belgian 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.

Belgian Endive needs ~1,495 GDD — county provides 943 GDD May not mature

Belgian Endive Planting Timeline — San Juan County, CO

Belgian Endive Planting Calendar

Activity When Date Range
Start Indoors May 14 May 14 – May 28
Transplant Outdoors June 18 Jun 18 – Jul 2
Direct Sow June 4 Jun 4 – Jun 25
Harvest October 8 Oct 8 – Dec 3
Fall Sowing June 30 Jun 30 – Jul 14

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 Transplant Outdoors Fall Sowing
August
September
October Harvest
November Harvest
December Harvest
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

110–150 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

82 days in San Juan County

Growing Tips for Belgian Endive in San Juan County

Direct sow Belgian Endive outdoors after June 18 in San Juan County when soil has warmed and frost danger has passed.

Your 82.0-day growing season in San Juan County is tight for Belgian Endive (110.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.

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

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

General growing tips

Grow chicory roots in the garden during summer, then dig in fall. Trim tops and force roots in moist sand in a dark cellar at 50-60F. Chicons emerge in 3-4 weeks.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Belgian Endive in San Juan County, CO?

San Juan County is in Zone 5a with an average last frost of June 18. Plan your Belgian Endive planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Juan County, CO?

San Juan County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 18 and first fall frost is September 8.

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Your San Juan County Garden Planner — Free

A 24-page printable planner built for San Juan 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 San Juan County, CO. 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.