When to Plant Watermelon in Marshall County, OK
Marshall County, Oklahoma gardeners: here's your May plan
We've pulled the most time-sensitive tasks for Marshall County, Oklahoma this May and put them front and centre. Tackle them in order.
Coming up in June — start thinking about
- First harvests: watermelon
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.
Marshall County, Oklahoma is in USDA Zone 8a. The average last spring frost is March 24 and the first fall frost is November 12, giving you a growing season of approximately 233 days.
At an elevation of 520 feet, Marshall County receives approximately 23.7 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Watermelon during the growing season.
Marshall County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.8
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 Marshall County
How your county's soil matches Watermelon's growing requirements.
Soil pH
Your soil pH (6.2–7.8) overlaps with Watermelon's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Marshall County is excellent for Watermelon — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Watermelon.
Organic Matter
Organic matter is moderate (3.5%). Annual compost additions will help Watermelon.
How to Plant Watermelon
Succession Planting Watermelon
Sow every 8 weeks. Last sowing by Aug 04 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Watermelon
Watermelon needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Watermelon Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.5" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | 6.5" | 1.6" | 4.9" | 🚿 Regular watering |
| Apr | 6.5" | 2.3" | 4.2" | 🚿 Regular watering |
| May | 6.5" | 4" | 2.5" | 💧 Light watering |
| Jun | 6.5" | 3.4" | 3.1" | 💧 Light watering |
| Jul | 6.5" | 3" | 3.5" | 🚿 Regular watering |
| Aug | 6.5" | 2.8" | 3.7" | 🚿 Regular watering |
| Sep | 6.5" | 2.4" | 4.1" | 🚿 Regular watering |
| Oct | 6.5" | 1.3" | 5.2" | 🚿 Regular watering |
| Nov | 6.5" | 0.9" | 5.6" | 🚿 Regular watering |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Marshall County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Watermelon 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.
Watermelon Planting Timeline — Marshall County, OK
Watermelon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 24 | Feb 24 – Mar 10 |
| Transplant Outdoors | April 7 | Apr 7 – Apr 21 |
| Direct Sow | March 31 | Mar 31 – Apr 21 |
| Harvest | June 16 | Jun 16 – Aug 4 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| 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: acceptable
🗺️ USDA Zone
Zone 8a
📆 Growing Season
233 days in Marshall County
Growing Tips for Watermelon in Marshall County
Direct sow Watermelon outdoors after March 24 in Marshall 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.
Marshall County receives only 24" of rain annually. Watermelon needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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.
Recommended Watermelon Varieties for Marshall County
Full-size melons that thrive with your long season
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Watermelon in Other Locations
Frequently Asked Questions
When should I plant Watermelon in Marshall County, OK?
Marshall County is in Zone 8a with an average last frost of March 24. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marshall County, OK?
Marshall County, Oklahoma is in USDA Hardiness Zone 8a. The average last spring frost is March 24 and first fall frost is November 12.
Your Marshall County Garden Planner — Free
A 24-page printable planner built for Marshall County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.