Grasses

Grass enables many plants plants to grow on it, and covers most of the aboveground landscape. There are six types of grass: Normal, Corrupt, Crimson, Mushroom, Jungle and Hallowed.

Grass types

 * Normal grass spreads over Dirt Blocks. Above ground grass blocks will grow Mushroom, Daybloom, flowers, and weeds, all of which can be cut with any tool or weapon. If a grass block has room below it, vines will grow downward from it. Grass is necessary in order to plant trees, Pumpkins, and Sunflowers. Grass does not spread below 0 elevation, but can be placed in lower layers block by block using the Staff of Regrowth or Grass Seeds. This grass will not grow flowers and tall grass, and trees planted on it will never mature. Grass occurs naturally above ground, but it may also be planted by using Grass Seeds bought from the Dryad.


 * Corrupt grass converts normal grass, and spreads over Dirt Blocks in lieu of normal grass. Above ground Corrupt grass will grow Vile Mushrooms, Deathweed, corrupted flowers, and weeds, all of which can be cut with any tool or weapon. In addition, Corrupted thorns will grow from Corrupted grass in any condition. Vines do not grow from Corrupt grass. Like normal grass, it does not spread below 0 elevation. This type of grass occurs naturally in Corrupted areas and may also be planted with Corrupt Seeds dropped by the Eye of Cthulhu. A large enough amount of Corrupted grass will turn the area into a Corruption biome. In Hardmode, Corrupt grass will convert blocks that are up to three squares away into their Corrupt variants. This includes turning Jungle grass and normal grass below 0 elevation into Corrupt grass. It also gives off particles.


 * Crimson grass converts normal grass, and spreads over Dirt Blocks in lieu of normal grass. It can sprout Vicious Mushrooms, the counterpart to Vile Mushrooms. It acts similar to Corrupt grass, but instead of the Corrupted thorns, Crimson vines will grow from the bottom of Crimson grass and also spread the Crimson. It can be grown with Crimson Seeds, and can be spread with the Clentaminator or Crimson blocks.


 * Mushroom grass spreads over Mud Blocks and will grow Glowing Mushrooms and Giant Glowing Mushrooms and can be found underground at a depth of 0 feet or below. Patches of mud seeded with Mushroom grass can be found in some caverns underground, generally with several tall Giant Glowing Mushrooms. Mushroom Grass Seeds are an uncommon drop from Glowing Mushrooms and Giant Glowing Mushrooms. Mushroom grass glows faintly and can be used as a natural light source. Mushroom grass is unaffected by Corruption or Crimson, but the uncovered mud is. When above ground, Mushroom grass and the Mushrooms on it actually grow faster.


 * Jungle grass spreads over Mud Blocks at any depth, and will grow Jungle vines, Jungle thorns, Moonglow, Jungle Spores, Jungle Roses, and Nature's Gift. Jungle grass occurs naturally in the Jungle and Underground Jungle area but can also be planted from Jungle Grass Seeds which are a rare drop from Jungle grass weeds and glowing flowers. Jungle plants grow underwater in contrast to other plants. Similar to Mushroom grass, Jungle grass spreads faster above surface level.


 * Hallowed grass converts normal grass, and spreads over Dirt Blocks in lieu of normal grass. Aboveground Hallowed grass will grow Mushroom, Daybloom, and flowers, similar to normal grass. Like regular grass, Hallowed grass does not spread below 0 feet elevation. Hallowed grass does not occur naturally until a world enters Hardmode, and may be created with Hallowed Seeds sold by the Dryad in Hardmode or with Holy Water. A large enough amount of Hallowed grass will turn the area into a Hallow biome. In Hardmode, Hallowed grass will convert blocks that are up to three squares away into their Hallowed variants, although it does not turn Jungle grass into Hallowed grass. It gives off a sparkle particle effect.

Growth
Grass of any type spreads from existing blocks to other blocks of the correct soil type. Corrupt, Crimson, and Hallowed grass can even – with certain restrictions – spread to and convert each other.

If painted grass spreads to adjacent Dirt/Mud Blocks, it will spread the paint too. Furthermore, tall grass, flowers, or Glowing Mushrooms growing on the colored grass will take on the same color. This does not extend to trees, Giant Glowing Mushrooms, or dye plants.

Trivia

 * There are unused graphics for two other grass types in the game's files. One is a yellow-green grass akin to Jungle Grass, although it is tiled on dirt. Its internal name "Tiles_2_Beach.png" implies that it was originally intended for the Ocean. The second is a variation of Flesh Blocks, tiled to work as a grass.
 * Crimson grass is referred to as "FleshGrass" internally, so the second grass variation may have been an early crimson grass sprite.

History
Gras Herbe 草