This is for the Block. For the item Grass, see Tall Grass
Grass Blocks are one of the most well-known blocks in Minecraft, as well as one of the most common. Before Minecraft PC 1.6, the logo was a Grass Block. Now it is a crafting table. On other versions though, Grass Block is still the logo.
Grass Block has no real use, it can't be crafted, cant be used as a crafting ingrediant, and doesn't look very nice in buildings. Though, on your first day of Minecraft, you will make your house out of Dirt, because if you mine grass with anything other than a Silk-Touch tool, it will drop as Dirt.
Grass Blocks can spread if they are out in a light level of at least 9. If the are covered by a block, they can die. Animals spawn on Grass Blocks. Sheep eat grass, converting it into a dirt block and re-growing the sheep's wool (if sheared). Grass can also grow even if it is under a transparent block, such as Glass.