Tutorial:Slime farming
Slime farming is a method of automatically spawning and killing slimes to easily obtain slimeballs, which can be crafted into slime blocks.
Both slime blocks and sticky pistons, which are crafted using slimeballs, are essential in many redstone builds. Slimeballs can also be crafted into magma cream, which is needed for brewing potions of fire resistance. Because slime blocks break instantly when hit, they are useful for quickly displacing and clearing out volumes of water in an ocean monument, even when under the effect of Mining Fatigue inflicted by an elder guardian.
Method
Pre-build
Slime farms can be built in a slime chunk or swamp biome.
Every chunk that is generated in a world has a 10% chance of being a slime chunk. Within slime chunks, slimes can spawn when Y < 40. To build a farm, a slime chunk must first be located by either exploring underground or using an external tool like the Chunkbase Slime Chunk Finder web app to locate chunks for your game seed. Slime chunk farms also require an underground room to be dug out within the slime chunk before the farm is constructed. It may also be necessary to light up or otherwise spawn-proof surrounding caves to prevent other mobs from spawning and improve the rates of the farm. Additionally, the chunk can be mined out all the way to the surface for further spawn-rate improvements.
| Chunks mined | Probability of finding at least 1 slime chunk (%) |
|---|---|
| 07 | 52.17 |
| 14 | 77.12 |
| 16 | 81.47 |
| 22 | 90.15 |
| 29 | 95.29 |
In swamps, slime spawning can occur between Y=51 and Y=69. A swamp-based farm has the advantage of not requiring any digging prior to building the farm, and the size of the farm is not limited, unlike the slime-chunk method, although the spawn rates in swamps are lower compared to slime chunks.
Spawning
The first step in constructing either farm is the spawning place. In most farm designs, spawning platforms are created which spawn slimes that are then moved to a killing trap, usually a drowning trap to split larger slimes down and dispatch the smallest size. Spawning pads are usually constructed with a 2½-block gap using slabs, to allow all types of slimes to spawn. It is important to illuminate the spawn platforms a bit to allow slimes to spawn while preventing other hostile mobs from spawning. In slime chunks, slimes spawn in any light level, whereas slimes in swamps require a light level of 7 or less, spawning more often in lower light levels. Swamp-based farms can use brown mushrooms on every spawning space as they produce a light level of 1, preventing other mobs from spawning and optimizing slime spawns (see Tutorials/Mushroom farming for more on obtaining mushrooms).
When the farm is operating, a player must be within 128 blocks of any possible slime location in order to allow the slimes to spawn within the farm and prevent them from despawning. Therefore, a specific location for a player to AFK should be decided. All areas outside the farm should be spawn-proofed within 128 blocks of the player to prevent other mobs from spawning, keeping the hostile mob cap as low as possible. In a swamp-based design, this can be easily achieved by placing the AFK location up above the farm such that the farm is just barely within the 128-block range. Any surrounding terrain still within that range can be easily spawn-proofed.
Transportation
The second step in building a slime farm is a method of transporting the slimes to the desired killing location. This is usually done by placing an iron golem to lure the slimes to the desired killing spot. It is important that the slimes must not damage the iron golems to ensure the golems never need to be replaced or repaired.
In pre-1.8 farms, this is usually achieved by using 'canals' of water separated by signs. As slimes can swim in snapshot 14w06a and above, specific water placement is required in Java Edition 1.8 and above.
Killing trap
The final step in building a slime farm is the killing trap. A quick and lossless method for killing slimes is using magma blocks, wither roses or soul campfires. A hopper minecart track underneath the magma blocks can be used to collect the drops. If soul campfires or wither roses planted on soul sand are used, hoppers can be placed directly beneath these blocks.
In older versions, it may be necessary to first separate the slimes into different sizes before killing them, usually achieved using a drowning trap. The largest type of slime is split to the medium size, and medium to small. The slimes are then taken off to another trap to be killed, usually another drowning trap. Separation trap could be used as a killing trap also.
Alternatively, a water stream carrying the slimes flowing into a cactus trap can be used. Hoppers around the base of the cacti then collect the drops. This has the advantage of killing all sizes of slimes without the need for separation. A downside of this method is that the cacti destroy around 20% of the slimeballs that are dropped.
For an interesting option, vindicators named "Johnny", or zoglins attack all slimes, but the slimes never retaliate.
Item collection (optional)
To automatically collect the slimeballs produced by the farm, create a hole below the end of the trap, with hoppers feeding into one or more double chests.
Potion of Oozing
Update 1.21 introduced Potions of Oozing, brewed using a slime block. They are a very easy way to farm for slime without having to locate slime chunks or build an elaborate farm. To create a potion-based farm, breed many animals (such as chickens) in a small area, using fences or blocks to keep them in. Then, throw a Potion of Oozing onto them, along with a harming potion (or just kill them with a sword). Every time a mob with the Oozing effect dies, slimes will spawn, which can be killed for an easy source of slimeballs.
Designs
Before 1.19, most designs were based on slime chunks located under the ocean, since only drowned spawn in oceans, and you would only have to clear a few caves when building the farm. After 1.19, a lot more swamp-based slime farm designs became popular.
