Grass Seeds

Grass Seeds are used to plant Grass on Dirt Blocks. They are sold by the Dryad.

This item becomes obsolete once the player finds a Staff of Regrowth as it has the same effect, but for free and with unlimited uses.

Use
Overall, there is not much point in spreading Grass, as most of the surface of the world is already covered in it. It is argued that since grass doesn't grow at negative elevations, Grass patches can be used to mark your way Underground, but a Torch will fill the same role, while also granting the player light. However, they can be used to plant on flat areas to create a Tree Farm, or in a layering formation to create a Mushroom Farm.

Another use would be to create artificial Floating Islands with grass