I'm not sure if I completly understand your question but here I go;
The point of transplanting and not growing in just one medium'ish sized plant from seedling to harvest is, that a big pot will be "too much" for a seedling. It takes more water and it holds onto the water longer. A seedling no way needs that much water and that will harm the roots and the plant.

Hope I answered your question, and that's all info I got from posting/getting answers and reading :jointsmile:
poker2 Reviewed by poker2 on . Germination/Growth Question Why not just germinate and grow the whole cycle in the same pot or medium? Isn't the whole point of indoor gardening to mimic nature as closely as possible? I hope this is not a stupid question, I have just never seen it asked or answered. Rating: 5