Southern Louisiana's hot summers and abundant humidity limits the types of grapes that grow successfully. Seedless varieties to grow here are even less numerous. Muscadine grapes, or scuppernongs, are best suited to this area's climate.
Among muscadine grapes, the variety Fry Seedless is well-suited to southern Louisiana counties. European grapes falter in the humidity, but hybrids of European and American fox grapes fare better. Recommended varieties include Himrod, Flame Seedless and any of the Mortensen hardy grapes.
Planting other varieties of seedless grapes, including some European types like Thompson Seedless, may be successful in southern Louisiana. The humidity negatively affects the plants and fruit production, but a small crop is possible.
For grapes to prosper in the oppressive Southern humidity, make sure to plant in a well-drained soil and in sunny exposures. Increase row spacing to ensure good air circulation among vines and plant on hillsides for improved air movement.