When to Plant Watermelon in Washington County, RI
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.
Washington County, Rhode Island is in USDA Zone 6b. The average last spring frost is April 23 and the first fall frost is October 21, giving you a growing season of approximately 181 days.
At an elevation of 519 feet, Washington County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Watermelon during the growing season.
Washington County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.6
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.
Plant Water Budget
Watermelon Planting Timeline — Washington County, RI
Watermelon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 19 | Mar 19 – Apr 2 |
| Transplant Outdoors | May 7 | May 7 – May 21 |
| Direct Sow | April 30 | Apr 30 – May 21 |
| Harvest | July 16 | Jul 16 – Sep 3 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
70–100 days
Soil pH
6 – 7.5
USDA Zone
Zone 6b
Growing Season
181 days
Growing Tips for Washington County
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 Washington County, RI?
Washington County is in Zone 6b with an average last frost of April 23. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Washington County, RI?
Washington County, Rhode Island is in USDA Hardiness Zone 6b. The average last spring frost is April 23 and first fall frost is October 21.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Washington County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.
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