A lawn.
It is usually referred to as the lawn.
grasscutter
backyard front yard
An open space between woods., Ground (generally in front of or around a house) covered with grass kept closely mown.
a roofed platform along the outside of a house, level with the ground floor
ground
A large area of grass, usually around a house or building.
The Tawakoni were a Caddoan people closely related to the Wichita and Waco, whose dwellings were conical in shape, made of a framework of poles covered with a thatch of grass, and were grouped about an open space which served for social and ceremonial gatherings. Couches covered with mats were ranged around the walls inside the house to serve as seats by day and beds by night. The fire was built in the center. All of these tribes were referred to as "Grass Lodge People" by other native tribes and in the Plains sign language. The links below take you to images of the grass-covered lodges used by these related tribes:
The Miwok people lived in Northern California. There are four subgroups (Plains/Sierra, Coast, Lake, Bay) and they all contributed different forms of shelter.Conical bark house with earth piled up on lower wall.Board houseConical pole frame covered with thatch of brush, grass or tulePortable conical house
A grass-covered plain in South Africa is called a savanna. A savanna is characterized by trees that are widely-spaced, with canopies that do not touch. Some parts have no trees at all. This allows enough sunlight to reach the plain, allowing grass to grow in abundance.
you have to add top soil.
It depends on where you are in the world. Grass or sod homes are made from blocks of turf cut out of the ground. The grass ties the sod together so it doesn't crumble when it gets wet. Grass huts are typically made by tying bundles of grass onto a framework of wood. The overlaps make a barrier against most rain.