Terraria: Easy AFK Boss Summon Farm (Pre-Hardmode)

Money can be hard to come by in Terraria, especially before Hardmode, which is why this farm exists. With it, you will be able to craft more boss summons than you can use, all without pressing a single key.

Before building the farm, there are a few prerequisites that need to be fulfilled.

First off, you will need to have killed Skeletron to have access to the mechanic and loot magnet.

Next, find a tall, flat area to build. The farm will need to be built high enough off the ground to prevent enemies from spawning below it, but low enough that harpies can’t spawn. 50 blocks off the ground should be fine. If you can’t a suitable area, consider lowering the floor with dynamite, just make sure that the farm is in the “surface” layer according to the depth meter. If the ground is absolutely flat, lava can be used to stop enemies from spawning there.

As for building the farm, it requires only a few wires but a ton of blocks, here is the list:

Loot Magnet accessory (very important)

2,400 Dirt

20 Dart Traps (For killing enemies and harvesting mushrooms)

190 Wires

11 Actuators

A 1/2 Second Timer

2 Water Candles

2 Doors

800 Walls

200 Minecart tracks

400 Building Blocks of your choice

1,000 Grass Seeds or a Staff of Regrowth

20 Corrupt or Crimson Seeds (Vile/vicious powder works too)

4 Chests (Used to prevent meteors spawns)

The first area of the farm is the AFK room, where you will slowly ride in a minecart and collect all of the items. To begin, place down all 200 minecart tracks in a straight line, then hammer the ends of the tracks to the “bumper” version, which repels player when they bump into it. Next, encase the tracks with building blocks, with a single layer underneath the tracks, and a layer 4 blocks above them, giving it a total height of 6 blocks. Next, simply place doors at either end and fill the room with background walls and water candles. The completed room should look like this:

As of 1.4, worms will not be able to spawn if you are in front of background walls or have not moved for 5 seconds, so you won’t need minions for protection.

The next part of the farm will the be the 11 rows of dirt where the enemies will spawn and mushrooms will grow.

Start at either end of the farm, placing the dirt in this configuration, 5 rows on the top, 6 on the bottom.
This maximizes space for vile mushrooms to spawn while still being in range of the loot magnet. Monsters will only spawn on the top portion and are also in range.
Next, simply extend the dirt platforms to the other end of the mine cart room, placing lots of grass and an occasional corrupt seed along the way. To spread the corruption faster, use vile powder instead of seeds. After the corruption has finished spreading, the farming area should look like this:
All that is left now are the dart traps for the mushrooms and rotten chunks. For the mushrooms, begin by placing a trap in the empty spaces between every layer of dirt, including one on the topmost layer. These will be used to uproot the mushrooms for easy collecting. Connect all of the traps to a timer, preferably a 1 second or faster. This is what the configuration will look like.
For the rotten chunk traps, place 3 temporary blocks above the top of the farm and 15 blocks back, then place a trap facing the farm. Go another 15 blocks back and place another trap, continuing this until there are 9-10 total traps with empty spaces between them. The spacings should look like this, only without blocks in the way.

Next, actuate the traps once then remove the actuators and temporary blocks used to build while connecting the traps with the timer. Make sure that every single trap is aligned and actuated, otherwise the damage output will be severely reduced. Now that everything else is built, place 4 chests across the top of the farm, these will prevent meteorites from ruining everything. The completed farm should similar to this:
Now that everything is complete, simply equip the loot magnet, switch on the timer, and ride slowly on the tracks.

Depending on how long you afk, you may end up with enough items to craft 20, 50, or even 100 boss summons, which can take quite a while to use up. However, using the correct weapons and fighting in the right arena will allow you to spend less time fighting and more time making those profits.

The arena you should use will depend on whether you are fighting the corruption or crimson boss. When fighting the Brain, feel free to use the farm as the arena, as he has no problem getting to you if he spawns far away. The Eater however, should never be fought on the farm, as he can fall through it, get stuck, and despawn. Instead, fight him on the floor, preferably in a flat area. Also, when the Eater spawns his segments will be all coiled up. Shooting him when he is like this will destroy a large portion of his health bar very quickly.

For both the Eater of Worlds and Brain of Cthulhu, weapons that excel at crowd control are essential to dispatching them in a timely manner. Some of the very best weapons include the Hellwing Bow paired with wooden arrows, followed by the Spinal Tap whip when combined with Obsidian armor, then finally the Sunfury flail. Other decent weapons include the Flamelash, but only against the Brain, and the Molten Fury paired with Unholy or Jester’s arrows. Don’t bother with the Star Cannon unless you have a farm made specifically for it.

After asserting superiority over the boss, sell the loot to the NPC with the highest happiness to squeeze out a little extra cash. Hooray! Now you should be able to reforge your copper pickaxe a few times!

There are a few extra things you should be aware of when using and making the farm.

The most persistent problem with this farm is the slime rain, which can sometimes kill the player during long afk sessions. Dart traps and lava count as player kills and will reliably spawn King Slime, who will teleport into the safe zone and kill you. As far as I am concerned there is no way to stop this, so check on the game every hour or so. It might be helpful to set your spawnpoint nearby just in case this happens.

Dart traps are essential to the farm but can be hard to obtain in the necessary quantities. Use Dangersense potions when looking for them, and search the Dungeon before anywhere else, as it has a high concentration of traps.