When to Plant Endive in Harper County, OK
Your May gardening checklist
Your garden in Harper County, Oklahoma is working on a schedule, even when you're not. Here's where you should be this May.
-
Start endive under lights
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
Get ahead of June
- First harvests: endive
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.
Harper County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 15 and the first fall frost is October 18, giving you a growing season of approximately 186 days.
At an elevation of 861 feet, Harper County receives approximately 21.5 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Endive during the growing season.
Harper County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.2
Drainage
Well Drained
Plant Planting Risk Windows
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 Harper County
How your county's soil matches Endive's growing requirements.
Soil pH
Your soil pH (6.4–7.2) overlaps with Endive's range (5.5–7.0), though not a perfect match.
Soil Texture
The loam soil in Harper County is excellent for Endive — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.6%). Annual compost additions will help Endive.
How to Plant Endive
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Endive
Sow every 5.1 weeks. Last sowing by Aug 14 to harvest before frost.
For a dedicated fall crop, sow by Aug 09.
Plant Water Budget
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 | — | 0.5" | 0" | ❄️ Dormant |
| Feb | — | 0.7" | 0" | ❄️ Dormant |
| Mar | — | 1.3" | 0" | ❄️ Dormant |
| Apr | 3" | 2.2" | 0.8" | 💧 Light watering |
| May | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 2.9" | 0.1" | 💧 Light watering |
| Aug | 3" | 2.3" | 0.7" | 💧 Light watering |
| Sep | 3" | 2" | 1" | 💧 Light watering |
| Oct | 3" | 1.3" | 1.7" | 🚿 Regular watering |
| Nov | — | 0.7" | 0" | ❄️ Dormant |
| Dec | — | 0.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Harper 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 Planting Timeline — Harper County, OK
Endive Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 11 | Mar 11 – Mar 25 |
| Transplant Outdoors | April 15 | Apr 15 – Apr 29 |
| Direct Sow | April 1 | Apr 1 – Apr 22 |
| Harvest | June 3 | Jun 3 – Jul 8 |
| Fall Sowing | August 9 | Aug 9 – Aug 23 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Only during dry spells
📅 Days to Maturity
45–65 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
186 days in Harper County
Growing Tips for Endive in Harper County
Direct sow Endive outdoors after April 15 in Harper County when soil has warmed and frost danger has passed.
Your generous 186.0-day season in Harper County allows multiple plantings of Endive. Sow every 22.0 days for continuous harvest.
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
Check more plant combinations with our Companion Planting Checker →
Endive in Other Locations
Frequently Asked Questions
When should I plant Endive in Harper County, OK?
Harper County is in Zone 7a with an average last frost of April 15. Plan your Endive planting based on this frost date — see the calendar above for exact timing.
What planting zone is Harper County, OK?
Harper County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 15 and first fall frost is October 18.
Your Harper County Garden Planner — Free
A 24-page printable planner built for Harper County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.