Propagation: The carambola is widely grown from seed though viability lasts only a few days. Only plump, fully developed seed should be planted. Veneer grafting during the time of most active growth gives the best results. Healthy, year-old seedlings of 3/8 - 3/4 inch diameter are best for rootstocks. Graft-wood should be taken from mature twigs on which leaves are still present and, if possible, the buds are just beginning to grow. Cleft-grafting of green budwood is also successful. Top-working of older trees has been done by bark grafting. Air-layering is less successful than grafting. The roots develop slowly, and percentage of success often is low. Trees are small and rather weak when propagated by this method.