My begonia - that I grew from seed - is flowering and looks great. My problem is that the plant needs supported by a stake. This wouldn't bother me so much but I stopped by a plant center and saw bigger begonias then mine and they needed no support and grew strong. I water when the plant is dry. It's in light soil and I fertilize with every watering - about 1/4 of suggested strength. Does anyone know what could be wrong? More light? Less water?

Thanks, bio