When Do You Plant Watermelons in Arkansas?

Planting Conditions

• Watermelons are tender annuals, which means that they cannot tolerate frost. For this reason, the actual conditions in your garden are more important than dates on the calendar, so keep an eye on the temperature and and wait to plant watermelons until all danger of frost has passed. The soil should also be warm -- 62 degrees Fahrenheit or greater -- and dry enough to work with. As a general rule, a handful of soil should fall apart not stick together when you squeeze it. If you'd like to get a head start, you can start watermelon seeds indoors in containers three or four weeks before the last frost.

Approximate Planting Times

• Climate varies significantly across Arkansas. North Arkansas, which is the coldest part of the state, is located in USDA zone 6, and can see winter temperatures as low as -5 degrees. South Arkansas is located in USDA zone 8 and seldom sees temperatures lower than 10 degrees. The University of Arkansas Division of Agriculture recommends planting watermelons outdoors sometime between May 10 and 15 in north Arkansas, and between April 15 and May 1 in south Arkansas.

Site and Soil Requirements

• Watermelons need warm temperatures and plenty of sunlight, so choose a location where they won't be in the shade during any part of the day. They grow best in well-drained sandy and loam soils with lots of organic content. The ideal pH for watermelons is between 6.0 and 7.0, but they can tolerate a pH as high as 5.5 or as high as 8.0. If you don't know the pH of your soil, test kits are available at most garden stores. Average moisture is best, so avoid overwatering or planting watermelons in wet, waterlogged soil.

How to Plant

• Watermelon plants have a tendency to sprawl, so give them plenty of room. Plant seeds about 1 inch deep in hills about 6 feet apart, and allow 7 to 10 feet between rows. If you start early by planting seeds in containers, use 3-inch-deep pots and plant three seeds in each one, then thin them down to the two healthiest plants after they germinate. Don't start watermelons in containers more than three or four weeks before you intend to transplant them, because larger plants don't transplant well.