Watermelon [Citrullus lanatus (Schrad.) Matsum. & Nakai] seeds of the tetraploid ‘Alena’ and the diploid ‘Sugar Baby’ were subjected to one of several treatments prior to germination at 17°, 21°, and 25°C, including lateral splitting, soaking in H2O (aerated or nonaerated), GA4+7, or benzyladenine (BA) for 24 hr, or in KNO3 for 5 days, followed by drying. These treatments were successful in increasing germination percentage of ‘Alena’ seeds. Soaking treatments increased ‘Alena’ embryo length. ‘Alena’ seeds possessed thicker seed coats, larger seed cavities, and absorbed more water than those of their diploid counterpart, ‘Sugar Baby’.