Tutorials/Cave spider farming

This tutorial teaches how to farm cave spiders.

Overview
Cave spiders can be dangerous enemies - they are shorter than a slab, one block wide, and apply the poison effect to the player. This makes them hard to farm. However, with some skills and care, it is possible. Although cave spiders don't drop anything that spiders don't, cave spider farms can be useful because they can yield a large amount of string and spider eyes, without the player having to find a dungeon with a spider spawner.

Preparation
Firstly, find an abandoned mineshaft that contains a cave spider spawner. The spawner area can be recognized by tons of cobwebs. The cave spider spawner will be in the center of the cobwebs.

Once a spawner is found, there are few things that need to be done before starting the farm. First of all, get rid of all the cobwebs with a sword or shears (sword yields string) and light up the area around the spawner. However, do NOT accidentally mine the cave spider spawner, because you will not be able to get it back.

The next thing to do is layout the area. For the best results, make a square with 4 blocks in between the monster spawned and each wall, and 1 block between the spawner and both, the ceiling and the floor. You should now have a 9 x 9 x 3 area, with the spawner in the center.

When working with the cave spider spawning area, it is strongly recommended to seal off the area you're working with, so that you are not in danger of mobs other than cave spiders attacking.

Collector
Once the area around the cave spider spawner is all set up, you can start building your farm. Most farms have 2 components, the collector and the grinder. The collector is the area around the spawner, which collects the cave spiders, and moves them towards the grinder. The grinder is what kills the cave spiders. They are usually killed by either the player or an iron golem, because most sources of damage do not damage cave spiders.

The spawning area in a cave spider farm is generally the same as for other monster spawner-based traps. However, remember that cave spiders are smaller - they can fit through gaps 1 block wide and 1/2 block tall. Also, remember that they can climb walls.

One way to get the cave spiders to go into the grinder is by pouring water on every block on one side of the spawning area. Then, dig down 1 for every block on the opposite side, place a water source block on each side of the ditch, and place signs over each block in the ditch. Now, all the water should eventually flow to one block. If you want to make sure that the cave spiders don't climb the walls, place water sources all along the top of each wall.

The block where all the water flows into should connect to the grinder room (make another channel if needed). Remember that you can stop the flow of water but still allow mobs and players to get through with signs.

Grinder


There are two types of grinders for any type of mob farm: a manual grinder and an automatic grinder. For a manual grinder, the player kills the mobs, and for an automatic, some other source of damage kills the mobs. For cave spiders, a manual grinder is cheaper and more efficient than an automatic, but requires the player to be there to kill the cave spiders.

Manual Grinder
Because of their size, ability to hold breath underwater, and ability to climb walls, lava, water, fall damage, and gravity grinders are ineffective or not as effective on caves spiders. Also, cactus isn't very effective, because cave spiders are small enough to go in between two cacti without taking damage (remember that cacti cannot be placed right next to each other). For this reason, it is very difficult to kill them automatically, without iron golems (see below). The easiest way to make a cave spider farm is to use a manual grinder.

Manual grinders require a hole that is too narrow for cave spiders but large enough to allow players to attack them easily. One simple way of making one is by placing two fence posts next to a closed door:

Automatic Grinder
One of the few ways to kill cave spiders without the player's aid is by placing iron golems in the collection chamber of the cave spiders. Place hoppers along the floor, all eventually connecting to a double chest. The iron golems will kill the cave spiders, and the loot will fall into the hoppers and go into the chest.

The disadvantage of using this method is that cave spiders will damage the iron golems as well, and eventually the iron golems will be killed. It is recommended to have an iron golem farm before trying to attempt this farm (otherwise, you will go through a lot of iron!). Also, remember that cave spiders will not drop spider eyes or experience if killed by some kind of damage that is not the player, so using iron golems to kill spiders will solely be a string farm.