Guide:Enemy farming

Monster farming is an essential part of Terraria. Some items have a very low drop rate; the way to get around this problem is to build a system that will constantly kill monsters until the desired item is obtained.

Monster farming basics
The most essential part to monster farming is knowing the basics of NPC spawning. Monsters will always spawn off screen, their spawn rates can be manipulated, and there is a limit to how many monsters can spawn in an area at one time.

Spawn rates can be changed by a number of factors. First, spawn rates are different depending on the biome and the time of day. Also, spawning is different depending on what depth layer you are in (e.g. dirt layer, stone layer). These factors also change what type of monsters spawn, so make sure you know the environment well before you start farming for a specific type of monster.

A few other effects will modify spawning rates: If there is a Blood Moon, the spawn rates will dramatically increase, and monsters will spawn even near your house. Water Candles and Battle Potions also greatly increase spawning rates. Both these items are recommended if you are farming monsters.

Another very important detail is that no monsters will spawn around a House if there are NPCs housed there currently. Note, a Blood Moon will override the no-spawning zone around houses.

Lava Trap
Lava traps are traps that use lava to kill monsters. Because of the high amount of damage done by the lava and the moderate ease to get the materials, a lava trap can make a very cost effective farm. Lava traps can be built by pouring a thin layer of lava into a pit (the thin layer of lava lets monsters be damaged while the drops remain undestroyed by the lava). A collection area below the pit is recommended for easy access to dropped items without having to go outside.

Lava traps can be used to farm a variety of monsters, but usually become outdated as the game progresses, due to more diverse monster types. Because there are a few types of monsters that farm exceptionally well with this type of trap, it should not be overlooked just because of its simple design.

Zombie/Demon Eye Farm
This farm uses a lava pit to kill Zombies and Demon Eyes. Zombies spawn in most above-ground biomes at night. A forest biome gives the most Zombie spawns because there are only a few other types of monsters that spawn along with Zombies. If you were to build a Zombie farm in the Jungle, you would get Jungle Bat spawns, Piranha spawns, and Jungle Slime spawns that would take the place of a Zombie spawn. A good place to build this farm is either in the middle of a flat forest or in the side of a cliff or mountain.

The primary items obtained from this farm are Shackles, Zombie arms, Lenses, and a decent amount of coins when built pre-Hardmode. Shackles can be a good starting defense item, and lenses can be crafted into a Suspicious Looking Eye, which is used to summon the Eye of Cthulhu. Shackles are a 1/50 drop from Zombies, so usually it will take a couple nights before you get your first one.

If you build this farm near your home (with NPCs), it will no longer work, because monsters do not spawn near your home. Blood Moons cancel this effect, so a substantial amount of loot can still be collected on those nights.

After Hardmode, this farm will still work, and may kill additional monster types. However, the rates for zombie spawns will be slightly lower.