Wax Begonia (Begonia Semperflorens White) flower seed is delicate and the consistency of powder. Start flower seed indoors 10 - 12 weeks before last frost. Press seeds onto the sterile potting mixture, but do not cover the seeds. Water from underneath to avoid fungus, and cover the flower seed tray with plastic wrap.
Transplant plants into good garden soil that is high in organic matter that will retain moisture keeping the soil cool. Begonia seeds care includes pinching the stems back if they look scraggly to encourage compact growth. Seeds require regular watering to look their best but will survive periods of drought.