Grass is a type of block in FortressCraft. The block coats the world naturally in the Temperate and Tropical world type found in the Climate Options page, as well as being placeable by the player. This block, when in a group of other grass blocks, will produce vegetation unless Vegetation is turned off in the Visual Settings menu. This block can be found in the 1st Block Wheel.

This block was released on April 8, 2011, with the release of the game.

As of Content Patch 10, there is an option for Alternative Grass in the Controls Menu. When enabled, this replaces the 'half-grass' sides with a full grass texture.