This is a valid question for a novice gardener as some hard shiny seeds do need the outer shell removed or scuffed (scarified) before planting however sunflower seeds are planted whole .Moisture will permeate the hard outer shell when the seed is planted (or sprouted on damp tissue etc ) . It will swell and split and a tap root will emerge followed very quickly by the dicot leaves (two "baby" leaves) unfolding. The halves of the outer hard casing initially are usually stuck to these leaves but fall away as the leaves harden.
This is a valid question for a novice gardener as some hard shiny seeds do need the outer shell removed or scuffed (scarified) before planting however sunflower seeds are planted whole .Moisture will permeate the hard outer shell when the seed is planted (or sprouted on damp tissue etc ) . It will swell and split and a tap root will emerge followed very quickly by the dicot leaves (two "baby" leaves) unfolding. The halves of the outer hard casing initially are usually stuck to these leaves but fall away as the leaves harden.