Guide:Artificial biomes

Artificial biomes are player-constructed biomes that will spawn the monsters and provide access to most of the other materials that this biome provides. Only certain biomes can be artificially constructed. These are useful for building gardens or otherwise farming for certain items. This guide will explain how to build such biomes.

Some biomes can be constructed within virtually any Layer, at any depth, while others have specific depth requirements. With the exception of the Meteorite biome, no biome will override the Underworld. Any biomes not mentioned below cannot be constructed artificially.

The Clentaminator is a very useful tool for making Artificial biomes, although it can be more expensive than other options. It is however way faster.

Forest
A Forest biome (also called "the Purity" in-game) is the default biome for the Surface layer. When none of the other conditions for a biome are currently fulfilled on the surface, then it is a forest biome.

A more proper forest can be grown by planting Grass Seeds on Dirt blocks. Trees can be grown with Acorns.

Usually players create an artificial forest only for farming trees and Mushrooms because there aren't many other things this biome is useful for.

Deserts
A Desert biome is defined by the presence of sufficient Sand blocks, in any Layer except the Underworld. Even a single block of sand can spawn desert enemies, as well as grow Cactus and Waterleaf. Deserts can be within any layer. It requires over 1000 blocks of sand to change the background into the desert background, and the presence of sufficient other biome-defining blocks on-screen will override this background.

A flat strip of sand, one block in height, is sufficient to be considered an artificial desert biome suitable for harvesting various Desert materials.

Hallowed, Corrupted, and Crimson deserts can be constructed from Pearlsand, Ebonsand, and Crimsand, respectively, in Hardmode.

Surface jungle
The Surface Jungle biome is defined by the presence of Jungle Grass on Mud blocks, but only on the Surface layer. Jungle Grass will cause the spawning of surface jungle enemies, regardless of how many tiles are present. 80 blocks of Jungle Grass, including plants that grow in the tiles above Jungle Grass, are needed to change the background and music into the Jungle biome's natural music and background.

If you have excess mud blocks, it's possible to build a part of skybridge out of mud blocks and plant jungle grass there. Since the trees will grow naturally there, it provides a lot of wood (and fallen stars as well) without the need to navigate through the hilly jungle terrain.

Underground jungle
The Underground Jungle biome is defined by the presence of Jungle Grass on Mud blocks in the Underground or Cavern layers below a certain depth. Which depth this is depends on the Map's size:

You can tell the difference between Jungle in the underground and true Underground Jungle by what monsters spawn and whether Jungle Spores grow naturally. If Hornets are spawning or Jungle Spores are visible, then it is a true Underground Jungle.

Snow
A Snow biome is defined by the presence of 300 or more Snow Blocks, Ice Blocks (including pink, purple, and red variants) or Snow Bricks. This will change the background and music into the Snow biome's background and music. Below the cavern layer, Underground Snow will be created instead.

Some Snow biome enemies require the presence of Ice Blocks to spawn, while others will appear along with the biome background and music, with particular enemies depending on depth and whether it's raining/snowing or not.

Ocean
An Ocean biome is defined by all of the following conditions:


 * The floor must be made of Sand at least one block thick. Pearlsand, Ebonsand, or Crimsand does not count.
 * There must be 2 or more tiles of Water atop the sand for Ocean monsters to spawn.
 * 7 or more tiles of water for Coral to grow.
 * This must be positioned within 250 blocks of either edge of the map.
 * This must be above a depth of 0, so within the Surface or Space layers.

Hallow, Corruption, and Crimson
The Hallow and Corruption biomes are defined by the presence of their respective hallowed and corrupted blocks, in any layer other than the Underworld. At least 100 Hallowed Grass, Pink Ice Block, Pearlstone, and Pearlsand defines the Hallow; tiles with hallowed plants (including 2-tile tall plants, but not trees) growing on top of hallowed grass also count. At least 200 Corrupt Grass, Purple Ice Block, Ebonstone, and Ebonsand defines the Corruption, with each tile of Vile Mushroom, Thorny Bush and other corrupted plants growing on top of grass counting. At least 200 Crimson Grass, Red Ice Block, Crimstone, and Crimsand defines the Crimson. Note that for purposes of defining a biome, each block of Crimson or Corruption will subtract 1 from the total count of Hallow blocks and vice versa.

If the world is pre-Hardmode, an artificial Hallow biome will not spawn its usual monsters; it will spawn Forest monsters instead.

Meteorite
The presence of 50 meteorite ore on the screen will transform any environment into a Meteorite biome. All naturally-occurring enemy spawns will be replaced with Meteor Heads, unless this is done in the ocean biome. This works even in the Underworld.

Mushroom
A Mushroom biome is defined by the presence of Mushroom grass, at least one exposed block of which will spawn Mushroom biome enemies if above the surface level of the world. At any depth, this grass will also sprout 1-block-tall Glowing Mushrooms and multi-block Giant glowing mushrooms. At least 100 tiles of mushrooms or mushroom grass are needed to start seeing changes to the music and background, although changing the water color in the biome may take more.

TIP If you need to make an artificial mushroom biome to get the Truffle NPC, converting the top of the dungeon into a garden works quite nicely, and gives you a sense of ironic power over the defeated skeletron.

Dungeon
The Dungeon must be below the surface level of the world, and consist of at least 250 blocks of Dungeon Brick. The player must also be standing in front of a naturally-placed Dungeon Wall -- if the player removes and replaces the wall at the same location or elsewhere, it will no longer count towards the requirement, making it impossible to create artificial Dungeon biomes elsewhere.

Furthermore, for a dungeon NPC to spawn, there must also be a natural dungeon wall tile directly above a dungeon brick surface, ensuring they never appear just outside of dungeons. Being in a dungeon biome prevents any non-dungeon NPCs from spawning. So if there is no appropriate spawn surface for dungeon mobs (brick and wall), then *all* spawns are blocked.

Spider Nest
A Spider Nest mini-biome is based on the presence of the special mottled grey/brown cave wall in these areas. Blocks in front of these walls will accumulate Cobwebs up to three tiles deep, and Wall Creepers (pre-Hardmode) and Black Recluses (in Hardmode) will spawn. It's not possible to move or collect this cave wall, so artificial biomes can't be created elsewhere, but a player could set up blocks in an existing nest to affect spawning / allow collection of cobwebs.

Underworld
The Underworld is defined as roughly the bottom 200 blocks of any world; at around this level, the music and background changes, Underworld enemies will spawn, and water will generally evaporate. An artificial Underworld cannot be created at any other depth.

Lihzahrd Temple
A naturally occurring Lihzahrd Brick Wall behind the player is required for Lihzahrd and Flying Snake spawns. Thus, while player may create spawning areas for these enemies by placing Lihzahrd Bricks, proximity to a natural temple is still necessary. Walls placed by a player, in game, actually block (all) spawns.

Lihzahrd Bricks count as jungle biome blocks, so can be used as a neater, quicker alternative to jungle grass. So blocks may be used in another area, to greatly increasing the Spawn Rate and NPC cap (in the forest or desert, for example), or to permit the summoning of Queen Bee.

Calculation Mechanics
Qualifying Blocks: Only blocks within a rectangular zone 50 tiles left and right, and about 43 tiles vertically, of the screen's centre are counted towards determining active biomes. At the edges of the world, when the screen stops scrolling, this reference point no longer matches the player's position.

For biome influencing walls (e.g. dungeon and lihzahrd brick), only the one tile directly behind the middle of the player's sprite is considered. This moves with the player at all times, even at the world's edges.

The reference point determining biome depth appears to be the top of the screen. When at a transition between Layers, resizing the screen may change the active biome, even while player remains totally static.

When the criterion for multiple biomes are met simultaneously, there is an order of precedence for which one sets the music, background scenery, spawn rate, innocent NPC spawns, etc. However, multiple biomes may be active simultaneously. This allows, for example, the possibility of two or more (or all) Biome Key Mold drops within one area.