When to Plant Watermelon in Grant County, OK
Watermelon is a sprawling vine crop that produces sweet, juicy fruits in hot weather. Varieties range from personal-sized icebox types to 50-pound giants.
Grant County, Oklahoma is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 27, giving you a growing season of approximately 199 days.
At an elevation of 564 feet, Grant County receives approximately 25.7 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Watermelon during the growing season.
Grant County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.2
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 Grant County
How your county's soil matches Watermelon's growing requirements.
Soil pH
Your soil pH (6.5–7.2) is within Watermelon's preferred range (6.0–7.5).
Soil Texture
The loam soil in Grant County is excellent for Watermelon — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.8%). Annual compost additions will help Watermelon.
How to Plant Watermelon
Succession Planting Watermelon
Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Watermelon Planting Timeline — Grant County, OK
Watermelon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 7 | Mar 7 – Mar 21 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Direct Sow | April 18 | Apr 18 – May 9 |
| Harvest | July 4 | Jul 4 – Aug 22 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
199 days in Grant County
Growing Tips for Watermelon in Grant County
Direct sow Watermelon outdoors after April 11 in Grant County when soil has warmed and frost danger has passed.
Common pests for Watermelon in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 3-4 weeks early or direct sow after soil is warm. Plant on mounds with plenty of space. Check ripeness by looking for a yellow ground spot and dull thump when tapped.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Watermelon in Other Locations
Frequently Asked Questions
When should I plant Watermelon in Grant County, OK?
Grant County is in Zone 6b with an average last frost of April 11. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grant County, OK?
Grant County, Oklahoma is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 27.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Grant County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.
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