The only way to make your first batch of these seeds is to use the Cross-breed Dragon's Breath Field recipe.
This uses 3 Southern Star Seeds and 3 Muddy Foot Seeds, and is of Expert level.
Plant the cross-breed and hope you get Poor Dragonsbreath Plants so you can get more seeds.
It is only possible to do after you have done the Cross-breed Muddy Foot Field recipe, as you need seeds from that (plant them first so you have enough for this and future use).