Grafted watermelon gains commercial foothold in Southeast

Hanna Raskin

Watermelon grafting, widely considered a kooky scheme before Clemson Cooperative Extension started studying it, is rapidly becoming accepted practice across the Southeast.

“Grafting is going to be here to stay,” state vegetable specialist Richard Hassell told a crowd of crop enthusiasts gathered last week for the Coastal Research and Education Center’s annual Field Day. Hassell has been updating the group on his project’s progress since its start in 2007.

According to Hassell, last year’s major breakthrough was the patenting of a process to prevent the regrowth of the disease-resistant rootstock joined to the fruit-producing top of another plant. If the rootstock sprouts, it won’t nourish the valuable fruit-bearing portion of the graft, so the melon withers away. Hassell says there has been international interest in the development.

The technique of watermelon grafting was introduced almost a century ago in Japan and Korea. It’s the dominant farming method in China, which produces more than half of the world’s watermelons, but the rootstocks used there to ward off disease tend to result in smaller, worse-tasting melons. Clemson, by contrast, has grafted its way to watermelons that have the same amount of sugar as standard watermelons.

Further tests on Fascination and Captivation melons, two of the most popular varieties in the U.S., showed grafted melons are firmer and last longer in the field.

“Growers are really interested because it can hold up as long as two weeks,” Hassell says. There is no harvest window for standard watermelons. “You don’t have a tractor, or it rained three inches, it doesn’t matter.”

Starting this year, an Israel-based grower is planting grafted watermelons near Hendersonville, N.C. and conducting trials across the country.

“I think we’re well on our way to getting this established in the U.S.,” Hassell said.