Grass is a surface type that can be found in a garden. The relevant Surface Packet is given by Leafos in Viva Piñata and is already available by default in Viva Piñata: Pocket Paradise and Viva Piñata: Trouble in Paradise. Most plants can be grown on grass. Some species of piñatas such as the Syrupent are attracted to grass and having a certain amount of grass is required to meet a certain requirement for the piñata.