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When to Plant Belgian Endive in Harmon County, OK

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.

Harmon County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is November 5, giving you a growing season of approximately 219 days.

At an elevation of 993 feet, Harmon County receives approximately 34.4 inches of rainfall annually with predominantly loam soil. Summer highs average 91ยฐF, providing good warmth for Belgian Endive during the growing season.

Harmon County, OK (Zone 7b) Long season
219 days
Last Spring Frost March 31
219 growing days
First Fall Frost November 5

Harmon County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (51 days to spare)
Start indoors: Feb 16 Transplant: Mar 23 🍅 Harvest: Jul 13 – Sep 7
Recommended (50%) ✓ Fits season (51 days to spare)
Start indoors: Feb 24 Transplant: Mar 31 🍅 Harvest: Jul 21 – Sep 15
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Aug 5 – Sep 30

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 Harmon County

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

Soil pH

Your soil pH (6.5โ€“7.5) overlaps with Belgian Endive's range (5.5โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Harmon County is excellent for Belgian Endive โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.0%) โ€” Belgian Endive will thrive.

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
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 796 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” 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 โ€” 0.9" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar 4.3" 2.3" 2" ๐Ÿ’ง Light watering
Apr 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
May 4.3" 5.1" 0" โœ… Rainfall sufficient
Jun 4.3" 5" 0" โœ… Rainfall sufficient
Jul 4.3" 4.1" 0.2" ๐Ÿ’ง Light watering
Aug 4.3" 4.8" 0" โœ… Rainfall sufficient
Sep 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Oct 4.3" 2" 2.3" ๐Ÿšฟ Regular watering
Nov 4.3" 1.3" 3" ๐Ÿšฟ Regular watering
Dec โ€” 1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Harmon County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~2,372 GDD — county provides 3,996 GDD Excellent fit

Belgian Endive Planting Timeline โ€” Harmon County, OK

Belgian Endive Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 โ€“ Mar 10
Transplant Outdoors March 31 Mar 31 โ€“ Apr 14
Direct Sow March 17 Mar 17 โ€“ Apr 7
Harvest July 21 Jul 21 โ€“ Sep 15
Fall Sowing August 27 Aug 27 โ€“ Sep 10

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

110โ€“150 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7b

๐Ÿ“† Growing Season

219 days in Harmon County

Growing Tips for Belgian Endive in Harmon County

Direct sow Belgian Endive outdoors after March 31 in Harmon County when soil has warmed and frost danger has passed.

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

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 Harmon County, OK?

Harmon County is in Zone 7b with an average last frost of March 31. Plan your Belgian Endive planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Harmon County, OK?

Harmon County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is November 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Harmon County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Harmon County, OK. Local conditions may vary. Last updated: April 2026.